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In this paper we shall give our last results on the setting of the doping level and the concentration profile of vapor grown Gallium Arsenide epitaxial layers. An operating process of doping by back-diffusion and our methods of characterization are given. REVUE DE PHYSIQUE APPLIQUEE TOME 6, MARS 1971, PAGE Les exigences actuelles de puissance et de fiabilite de dispositifs hyperfrequences realises a partir de couches epitaxiales d’arseniure de Gallium, imposent de la part du materiau des caracteristiques ameliorees concernant en particulier sa mobilite, son niveau et son profil de dopage. L’optimalisation de ces caracteristiques sous-entend un effort important, visant a maitriser les conditions de croissance et de dopage ; on parvient alors a un niveau constant dans la qualite du materiau. Nous donnerons dans cet article nos resultats recemment acquis dans ce domaine. 1. Procedes de dopage. La methode de croissance epitaxiale que nous avons utilisee est basee sur le transport du gallium en phase vapeur par le trichlorure d’arsenic [1] [2]. L’equilibre qui s’etablit alors entre les differents constituants gazeux au niveau de la source de gallium (portee a une temperature de 850 OC) se trouve deplace dans le sens favorable a la formation d’arseniure de gallium, lorsque les gaz entraines par l’hydrogene vecteur arrivent au voisinage des substrats places a 750 OC [3]. Le dopage de la couche deposee a lieu lorsqu’une faible pression partielle du dopant est assuree dans le flux gazeux responsable du transport. Jusqu’a present deux moyens permettaient d’obtenir ce resultat. Le premier, utilise pour le dopage au soufre, consiste a mettre en parallele avec le circuit de croissance, un second circuit amenant des vapeurs dopantes en tres faible concentration. Cette operation est delicate car il est difficile d’assurer une pression partielle a la fois faible et bien controlee. Le second moyen consiste a introduire dans la source de Gallium un dopant metallique (par exemple une quantite connue d’etain). Enfin, nous venons de mettre au point un troisieme procede, utilisant le phenomene de la retro diffusion gazeuse [4]. PRINCIPE DE DOPAGE PAR RETRODIFFUSION. Si en des points A et B d’une enceinte (Fig. 1) arrivent FiG. 1. Schema de principe du dopage par retrodiffusion gazeuse. simultanement des gaz X et Y dans le sens 1, il se produit une retrodiffusion dans le sens 2 d’une fraction du gaz X vers le point B. Cette retrodiffusion est fonction du rapport des debits des gaz X et Y. En placant alors entre A et B un element dopant susceptible de reagir avec le gaz retrodiffusant (sans reagir avec le gaz vecteur Y) on constate l’attaque du dopant et sa presence dans le flux gazeux s’ecoulant selon le sens 1. Le dopage qui en resulte est alors fonction de la retrodiffusion, elle-meme fonction exponentielle de la position du dopant dans le reacteur ; ce qui permet un bon controle, notamment pour les tres grandes dilutions. Pour obtenir une valeur determinee du niveau de dopage, il suffit alors de regler le debit du gaz vecteur Y, tout en maintenant constant de debit du gaz X. Cependant, l’application de ce phenomene au controle du dopage exige que la tension de vapeur du dopant soit negligeable a la temperature de l’enceinte (afin que le transport du dopant resulte uniquement de l’attaque chimique par le gaz X retrodiffuse). Article published online by EDP Sciences and available at http://dx.doi.org/10.1051/rphysap:01971006010500

There are many aspects in which the subject of copyright might be regarded by the writer of a paper appointed to be read before this Association. It might be treated historically, and dressed with amusing anecdote; instances of bad or good fortune attending on certain well-known compositions might be recorded; lessons might be drawn from the high rewards obtained by the comic song or the dance tune, as compared with the poor financial results realised by the classical work of high intention and, it may be, of high achievement. Or, again, each composer or publisher might well and effectively occupy the attention of a meeting of the Association for the limited period allotted for discussion in treating this subject of copyright from the standpoint of his own special grievance or experience or criticism, and in offering for acceptance his own peculiar remedy or suggestion for amendment of the law. Or, again (to give as illustrations two points in the law of copyright so special in their character that they will need no further notice in this paper), the reader might treat the subject from the side of paradox. Eg. gr.: it is a maxim in the law of copyright that there can be no copyright in immoral publications: can there be immorality in music? Could we apply this maxim and deny copyright to a musical composition so trivial, so commonplace, or with so many consecutive fifths in it as to amount to musical immorality? Or again, the fifth section in the Copyright Act of 1842 empowers the Judicial Committee of the Privy Council, on complaint that the proprietor of the copyright in any book (including printed music), after the death of its author, has refused to republish or allow the republication of the same, and that by reason of such refusal such book may be withheld from the public, to grant a license to the complainant to publish such book in such manner and subject to such conditions as they think fit; and the complainant may publish such book according to such license. Question raised: Would it be expedient to extend the principle of this provision to cases in the lifetime of the author, as, e.g., when the proprietor of the copyright in a musical composition has got possession of the plates and locked them up in his cellars, and refuses to reprint; and the composer, who sees in the publication of the work the passport to the recognition of his genius, laments the loss to the world of such a precious possession?

During the last twelve years I have communicated to this Society, often in collaboration with Dr. G. T. Prior, several papers descriptive of Bolivian minerals. These papers have dealt primarily with the species augelite, andorite, argyrodite, stannite, and chaleostibite, though many others have been examined and in some cases incidentally mentioned. The latter, as being of lesser general interest, or as not having led to sufficiently important results for separate publication, are now collected together in the present notes.

In ‘Nature’ of May 31, 1906, the senior author gave a preliminary account of a new Vesuvian mineral, which he had found amongst the products of the eruption of April 1906, and for which he proposed tile name chlormanganokalite. It was described as a hydrous chloride of manganese and potassium, occurring as deliquescent crystals apparently rhombohedral in form. A few days later, on June 5, 1906, Professor A. Laeroix described, before the French Academy of Sciences, a Vesuvian mineral which he thought must be identical with chlormanganokalite : he stated it to be an anhydrous chloride of manganese, potassium, and sodium, and he determined the deliquescent crystals to be monoclinic and psehdo-rhombohedral. In a later paper, Professor Lacroix rightly insists upon this identity.

This paper gives the results of an investigation at the Imperial Institute of a carnotite-bearing specimen received from South Australia.The material represented by the specimen is described by Mr. H. Y. L. Brown, Government Geologist of South Australia, as occurring about 2 miles SSW. of Teesdale's dam and about 20 miles ESE. of Olary railway station. He remarks : ‘The ore occurs as yellow and greenish-yellow incrustations and powder on the faces, joints, and cavities of a lode formation, which consists of magnetic titaniferous iron, magnetite, &c., and quartz in association with black mica (biotite) . . . . . . The outcrops traverse metamorphic gneissic micaceous granite and granite schist, into which dykes of granite and diorite have been intruded.’

In this paper an attempt is made to state and explain, in a simple manner, the essential features of the phenomena which are seen when plates of pleochroie minerals are examined in ordinary light.The pleochroie effects exhibited by minerals are usually studied in light of practically normal incidence. For the observation of facial colours, transparent crystals, or, better still, specially orientated cube-shaped pieces of minerals, are examined in ordinary light. In general, by this mode of observation, only facial colours are seen when ordinary light is used, and for the observation of axial colours the incident light must be polarized.

The mineral dealt with in this paper was sent for examination the Imperial Institute by Mr. J. B. Scrivener, Government Geologist to the Federated Malay States. It occurs on the river Sebantun, about half a mile above Salak North village, Kuala Kangsar district, Perak. The ground on which it was obtained was held on a tin-mining lease, but had to be abandoned owing to the presence of the unknown mineral, which rendered mining unprofitable.

The observation of the striking similarity both in chemical and mineral composition of the Baroti, Wittekrantz, and St. Michel meteorites (see the preceding paper) suggested the idea of testing how far such a close relationship applied to other cbondritic meteoric stones.The practical identity in chemical composition of different meteoric stones has been often pointed out. For example, A. E. Nordenskiöld showed in the case of the stones of Erxleben, Lixna, Blansko, Ohaba, Pillistfer, Dundrum, Hessle, Orvinio, and Stäilldalen that the percentage chemical compositions differed very slightly if the proportions of the metals, silicon, &c., were considered instead of the oxides.

The crystals to which this paper refers are found at Bail Hill, about three miles north of Sanquhar, in Dumfriesshire. At this locality volcanic rocks of Arenlg age outcrop in the midst of the greywacke of the Southern Uplands. The rocks are mainly lavas, and include some coarse-grained tufts which are composed chiefly of augite- and hornblendeandesites. Ill the andesitic fragments, there arc numerous porphyritic crystals of a black augite, which call be easily separated from the rest of the rock. Isolated crystals of augite and hornblende occur also in the matrix of the tufts. No mention of this occurrence is made in Heddle's 'Mineralogy of Scotland', and apparently the only reference to it in previous literature is the short petrographic description in the Geological Survey Memoir.

In the present paper the dispersion of the refractive indices of monoelinie felspars from four different localities is given, likewise that of the optic axial angle and of the optic axes in some of them.The method of investigation and instruments for these studies have been already mentioned in my previous paper. As the refractive indices and dispersion of the glass hemisphere of the total-reflectometer have not so far been given, I shall in the first place state the way in which they have been determined and their values and the degree of accuracy attainable, for the dispersion of the glass hemisphere differs to au appreciable degree from that of other instruments of the same kind.

The investigation of the Launton, Warbreccan, and Cronstad meteorites was undertaken with the object of placing on record descriptions of these stones. Launton and Warbreccan were found to conform very well with the type of Baroti and Wittekrantz, containing from 7-9 per cent. of nickel-iron, described in a previous paper. Cronstad, however, which contained as much as 18 per cent. of nickel-iron, showed so much variation from that type as to suggest a passage towards the rare Hvittis class of chrondritic stone containing even larger amounts of nickel-iron.

In a previous paper attention was drawn to the close similarity in mineral and chemical composition of chondritic meteoric stones. In the case of about forty chondrites it was shown that, apart from variations in the amount of nickel-iron, not only are the constituent minerals present in very similar amounts, but their chemical compositions vary to no very great extent. In that paper sufficient importance was not attached to the variations in the amount of nickel-iron.

To the Editor: —I have now been a reader of your valuable paper for more than a year, and do not see how I can possibly do without my weekly copy. The thing that kills the British medical journals is the length of their articles. It almost seems that every writer makes it his business to make his articles as long as he possibly can instead of the reverse. I trust, therefore, that you will not allow that vice to creep intoThe Journal. A busy man has no time to be bored with such long articles. I thought the article on "The Treatment of Hookworm Infection," published inThe Journal, February 23, was rather long, and contained tables that might have been eliminated with a summary.

In the Geological Magazine for 1918 there appeared three papers discussing the origin of tile system of cracks ill septarian nodules. Dr. A. Morley Davies opened the discussion in a paper where, after a summary of earlier literature, he again put forward an older idea. Without adducing evidence, he considered : (a)that interposition of particles between those of the original matrix caused expansion which set up tensile strain in the growing body ;(b)that the cracking of the nodule was due to the relief of those tensile stresses.

In the classification proposed by the author in a previous paper meteorites are divided into five groups according to the ratio of iron to nickel in the nickeliferous iron they contain. In the case of the meteoric irons such a classification, as shown by Farrington's list of analyses, is a natural one, since the structure of the irons, as revealed by etching, varies with the amount of nickel they contain. Thus Group 1, in which the metal is poor ill nickel, with a ratio of Fe to Ni of 13 upwards, includes nickel-poor ataxites, hexahedrites, and Coarsest and coarse octahedrites ; Group 2, in which Fe : Ni =8-13, the rest of the octahedrites from medium to finest ; Group 8, in which Fe : Ni = 5-8, nickel-rich ataxites; Group 4, in which Fe: Ni = 2-5, ataxites still richer in nickel; while Group 5 may include the doubtful Oktibbeha meteorite in which the ratio of iron to nickel is even less than one.

While it is customary to think of the entomogenous fungi as members for the most part of the groups Entomophthorales, Ascomycetes and Fungi Imperfecti, there are in literature several records in which such a habit has been attributed to certain Basidiomycetes. Among the latter may be mentioned the various species of Septobasidium and the form called Hirsutella entomophila by Patouillard. The present paper deals with certain fungi that are evidently closely related to the latter. It will be shown, however, that they should not be considered as Basidiomycetes, but rather that they should be looked upon as constituting a rather definite form genus of the Fungi Imperfecti, with which group they must apparently be associated until the perfect stages are found. The paper by Patouillard (I892) in which Hirsutella entomophila is described, although without illustrations, is otherwise quite comprehensive, and there is little doubt in the opinion of the writer that the fungus mentioned is closely allied to members of the group herein considered, and in fact it is looked upon as identical with one of them.

The study of the fungous flora of Porto Rico has received in recent years considerable attention from American mycologists. Their enthusiasm has been stimulated by the extensive collections made by Stevens, Fink, Whetzel and Olive, and has led to the publication of a series of papers which give us some conception of the richness of the mycological flora of the island. These studies are of importance, since they represent the first attempt on the part of American mycologists to gain a clearer knowledge of the fungi of the West Indies. A fairly complete account of the Uredinales has been presented in the publications of Arthur (2, 3) and Whetzel and Olive (22). but our knowledge of the pyrenomycetes is still far from perfect in spite of the numerous papers which have appeared dealing with the members of this group. Klotzch and Sintenis seem to have been the first botanists to

In Part I of this paper the actual frequency-distribution of igneous rocks as revealed by the latest edition of Washington's collection of analyses was examined, and compared with that of earlier records. An attempt wilt now be made to determine the law of this distribution–a necessary preliminary to any petrogenic application of the results. The silica frequency will be considered since this has been found to give a curve more characteristic of igneous rocks than does any other oxide Now Dr. Harker pointed out that the silica distribution of records published in 1903 did not obey any simple law such as that of the probability curve, and the same conclusion applies to the collection of 1917. However, when the empirical method of Karl Pearson was applied to analyse the curve into component curves of error, fairly simple conclusions resulted.

The optical dispersion phenomena of felspars at the alkalic and calic ends of the plagioclase series have been investigated by C. Viola and S. Kôzu, but for those of intermediate composition the data have been lacking. In view of the usefulness of the dispersion data of felspars for their determination in cleavage-flakes by the method to be described in the next paper, the present writer has made a study of the dispersion of certain intermediate plagioelases.

Recently H. E. Merwin employed an improved immersion method for determining refractive indices to identify certain salts of the system Fe2O3–SO3–H2O. In the present paper is described an application of the principle of his method to the determination of plagioclases in cleavage-flakes.

In April 1909 a paper on artificial reproduction of meteoric structure in alloys of iron aud carbon was read by the author before the Russian Mineralogical Society. In that paper special reference was made to the work of Sorby, who, to cite his own words, for ‘more than twenty years … commenced to carefully study the microscopical structure of iron and steel in order, if possible, to throw light on the origin of meteoric iron’. A brief survey of the work of Stodart and Faraday, of Osmond, Rinne, and Berwerth was also given and, subsequently, the structure of a carbon-steel containing 0.55 % carbon with perfectly developed Widmanstätten figures was described.

1. 1. We denote by r (n) the number of representations of n as the sum of two squares, representations which differ only in sign or order being counted as distinct; or, what is the same thing, the number of integral solutions of u 2 + v 2 , (1. 11) or the coefficient of z n in the expansion ( D ( z ) ) 2 = (1 + 2 z + 2 z 4 + 2 z 9 + ...) 2 = Ʃ ∞ 0 r (n) z n . (1. 12) If x is not an integer, or is negative, we write r (x) = 0.

has long been a matter of observation and experiment. With few exceptions, the experimental work has been carried out with field plantings where the groups of factors influencing infection could neither be isolated nor controlied. The limited number of controlled experiments dealing with the influence of environmental factors in the development of bunt have been largely upon Tilletia Tritici (Bjerk.) Wint. Very little is known concerning the temperature relations of Tilletia laevis Kiihn, except what is inferred from temperature and rainfall records during field plantings. Not all authors have stated with which of these species of Tilletia they were working, and hence some of the results are of uncertain application. There seems to be pretty general agreement that low soil temperatures are most favorable for infection by Tilletia Tritici. While Tubeuf (19, 20) believed that high temperatures promote bunt production, Volkart (21) concluded that lower soil temperatures favor the bunt. Hecke (6) found, with some exceptions, that early sowings of spring wheat gave higher percentages of bunt than late plantings. Munerati (9) obtained 92-100 per cent of bunt in wheat germinated at 7-8° C., while the same varieties gave 1.4-12 per cent when germinated at 18-20° C. In a more recent paper (10) he finds that seed germinated at 10-12° C. gave 13.2-39.3 per cent infection while the same two varieties gave 0-1.4 per cent bunt when germinated at 22-25° C. Heuser (7) secured 67.1-94.7 per cent bunt in three varieties germinated at 6-10° C. but only 1.8-6 when they were germinated at 16-22° C. Hungerford (8) secured higher infections in each of four moisture experiments at 9-12° C. than at 17-25° or 25-28°.

The study of the inheritance of disease resistance constitutes a problem of great economic and scientific interest and numerous investigators have contributed towards its elucidation in various groups of diseases. The present paper is concerned with studies on the inheritance of resistance to the loose smut of oats, Ustilago Avenae (Pers.) Jens., in a hybrid between a very susceptible variety, Avena nuda L. var. inermis (S.N. 30), and a very resistant one, A. sativa L. var. Black Mesdag (S.N. 70). Although the results here described relate to a single cross, investigations are in progress on additional ones between the same parents, as well as crosses involving other varieties. A few results on oat smut inheritance have previously been recorded. Wakabayashi (18) has pubiished some data on the behavior of the progeny of a cross between Red Rustproof and Black Tartarian to Ustilago levis (K. & S.) Magn., the former being resistant and the latter susceptible to the smut. No smut was observed among the F1 and F2 plants. In the F3 generation, however, twelve families out of a total of ninety-five were observed to contain a few infected individuals. Barney (1) has recorded more extensive data on three different oat crosses. One cross involved two very resistant varieties, Fulghum and Black Mesdag; a second cross was between the resistant Burt and the susceptible Swedish Select; and the third cross was between two susceptible varieties, Turkish Rustproof and Golden Rain. Barney interpreted his results on the basis that resistance in the first cross depended upon three different factors, in the second upon two, and in the third upon only one. Reed and Stanton (16) have described their results with a cross between

In this paper further evidence is put forward in support of a previous paper on the subject. Very soon after the reading of that paper, A. E. Mitchell read a paper before the Chemical Society on a closely related subject. Working quite independently, and employing other methods of investigation, Mitchell arrived at conclusions in close agreement with those detailed in the former paper. H.L.J. Bäckström has criticized Mitchell's paper, raising some objections 'against the experimental evidence produced aud the … way of interpreting it'. Where Bäckström objections touch on anything in Mitchell's paper which is incidentally akin to any of the work described in this or the earlier paper, they will be discussed herein.

The twofold division of metamorphic rock-series into (a) Isophysical rock-series and (b) Isochemical rock-series, as proposed by P. Niggli in his paper, 'Die Gesteinsassoziationen und ihre Entstehung', introduces into metamorphic petrology two very useful terms, which will be of service in the metamorphic researches that await the attention of the petrologist.Among such investigated rock-series one may call to mind the studies on the chloritoid-schists of the St. Gotthard massif," the glaucophaneschist suite of the Bagne valley (Wallis), the calc-silicate series of the Trondhjem region, the contact rocks of the Kristiania and Comrie areas. Of these the last are particularly illustrative of an isophysical rock-series, wherein a chemically wide group of assemblages conforming to the composition of shale-limestone sediments is represented in the free-silica and quartzless hornfelses.

In a proper recently published by Prof. Vegard is contained an analysis of the structure of the zircon group of crystals, which belong to the tetragonal holohedral class, the axial ratio being approximately a : c = 1 : 0.656.As the present work was completed when the above paper appeared, it is interesting to find that the principal deductions concerning the structure of zircon, ZrSiO4, are confirmatory. The parametral values are, however, slightly different. This difference, though small in itself, is found to introduce larger discrepancies between the observed and calculated intensities of reflection.

Our knowledge of the fungi of Santo Domingo is comparatively meager. Berkeley (5) appears to have been the first to make a study of the fungous flora of this Island. His work is based on a collection made by A. Salle and eighteen of the sixty-seven species studied were described as new. Later Berkeley (6), in connection with his studies of Australian fungi, reexamined his Santo Domingan species, Peziza domingensis, and made it the type of the new genus Phillipsia. With the exception of a few short papers by Gonzalez Fragoso and Ciferri (13), (14), (15), (16), (17), Ciferri and Gonzalez Fragoso (9), dealing with the fungi, and a note by the writer (28) on the myxomycetes of that Island, all references to Santo Domingan fungi are scattered within the literature of other regions. The fungus Aecidium Cordiae P. Henn. was described from a specimen collected in Santo Domingo, by Ehrenberg, and pub? lished by Bresadola, Hennings and Magnus (7) in connection with their studies on Porto Rico fungi. Leveille (18) and Lloyd (19) refer to the fungi collected by Poiteau in Hispaniola. It is doubtful, however, whether these fungi belong to Santo Domingo proper since there is no record of Poiteau having ever collected outside of Haiti. Fee (11) describes a new species of Sphaeria from this Island, S. divaricata, which was renamed by Saccardo (21) Xylaria divaricata (Fee) Sacc. Saccardo (l.c.) also re? examined most of Berkeley's Santo Domingan species of Hypo? xylon and changed them to Xylaria. Reference is also made by Saccardo (22) to a rust described by deCandolle from this Island. In his studies of the Uredinales, Arthur (1), (2), (3), (4) includes Santo Domingo in the geographical distribution of many of the species. Burt (8) refers to species of Stereum collected by Taylor and by Stevenson; Olive and Whetzel (20) extend the range of Endophyllum Stachytarpetae to this Island, wThile the writer (29) 66

As the speaker representing the Mathematical Association of America at this session I propose this morning to call your attention to one of the more important duties of a mathematician, namely, the duty of explaining as clearly as possible mathematical truths and discoveries both to his fellow mathematicians and to students of mathematics in general. The American Mathematical Society is especially devoted to the encouragement of research and the secretary of that society has called to your attention during this meeting the remarkable increase in the number of papers presented annually to the Society during the past five years. This increase has been such as to make the problem of publishing the results of mathematical research in America a very acute and difficult one. At the same time it has become more desirable than ever before that the papers published in our American journals should be as clear and as easily readible as possible. The Mathematical Association of America is especially concerned with the teaching and exposition of mathematical truth and it is pretty generally agreed that it is highly desirable that care should be taken to make this teaching and exposition to students as good as possible. I fear, however, that some of my friends who are particularly interested in research agree to this in a rather condescending manner; their tone implying that, whilst nothing should be done to discourage anyone beginning the study of mathematics, such care is not so necessary nor even so desirable when writing for fellow mathematicians. The underlying idea is that a competent mathematician usually prefers to glance at a paper, see the results arrived at, and then derive these results in his own individual manner. I believe that this opinion is not justified by the facts and in support of this belief I shall mention two instances which have recently come to my attention where mathematicians of great competence failed, through a lack of detail or of clarity in available expositions of known results, to arrive at immediate and important corollaries of these results. I shall be happy if my talk this morning tends to make the editors of our mathematical journals insist more definitely on clearness of exposition when considering papers submitted for publication. One can surmise that the writers of at least some of our papers set down their results with the referee of the paper more in mind than the prospective readers. They neglect, therefore, to state or. emphasize points which they think will be familiar to the referee. Of course this is unfortunate since there is us'ually a one-to-one

This paper presents the results of an investigation of the granite composing the eastern part of Bodmin Moor, Cornwall, as mapped on Sheet no. 337 of the Geological Survey. The work was undertaken on the suggestion of Dr. J.W. Evans, and comprised the field- and laboratory-work necessary for a detailed study of the petrology and tectonics of the area.The boundary of the granite, as mapped by the Geological Survey, has been retained, and also the distribution of the two main granite types ('coarse' and 'fine') shown on the Survey map. The coarse granite, however, has been sub-divided into two varieties, and it has been found practicable to map the distribution of each (fig. 1).The killas inclusions in this granite have not hitherto been studied, and these have received due attention. Similarly, the minor intrusions described include some that have not been previously recorded.

Ever since the classic work of the Tulasnes (11), the position of the Nidulariaceae as Basidiomycetes has been definitely established. Later authors have contributed much to our knowledge of the taxonomy and morphology of the group, but surprisingly little has been added to what the Tulasnes published concerning the basidia. This is partly to be explained by the fact that the time during which spores may be found on the basidia is comparatively short, and the spores are shed and the basidia collapse long before the peridioles are exposed. The Tulasnes note that after their discharge the basidiospores of Cyathus striatus develop a thick spore wall, and Sachs (8) observed a similar change in the spores of Crucibulum vulgare, but these observations seem not to have been extended to other species. Besides the authors cited, R. E. Fries (4, 5) and Walker (12) have published excellent figures of the basidia of the Nidu? lariaceae, but these were incidental to morphological and cytological studies, and were made from fixed and stained sections. It seemed desirable, therefore, to make a comparative study of the basidia of as many species as possible. The present paper is based on the examination of three species of Cyathus, one of Crucibulum, and one of Nidularia, of all of which living as well as dried material was available. The dried specimens were soaked in water for at least an hour, then very thin freehand sections were cut and mounted in dilute potassium hydroxide solution, sometimes stained lightly with eosin. Living material was sectioned similarly and either examined untreated or killed in Gram's Iodine solution and stained with eosin. In all five species studied, it was found that the basidia appear when the basidiocarp is less than half its full size. They are at first

In their paper on 'The structure of α and β quartz', Sir William Bragg and R. E. Gibbs touch on the question of twinning of quartz, showing how X-ray determination of structure can help to explain the different types of twinning. They only mention, however, twinning with parallel axes and twinning on . It would be interesting to see this extended to the examination of all known laws of twinning of α-and β-quartz. There is, however, still much doubt about the laws of the twinning of quartz. Many varieties of twins have been described, but a number of these are much open to doubt, while some are decidedly nonexistent. G. Friedel has within recent years published valuable papers on the laws of twinning in general, and has made more special application of his theories to the laws of twinning of quartz. It would be interesting to see how far all cases of well-established quartz twins occurring ill nature confirm his results.

The system of intrusive sheets in the Lower Carboniferous formations of the north of England, familiar to geologists throughout the world as the Great Whin Sill, has a voluminous early literature which it is unnecessary to summarize here. It will be sufficient to refer to the classical papers by Topley and Lebour on the field relationships (1) and by Teall on the detailed petrography (4), each of which contains an ample bibliography of the earlier literature. The most recent general account is by Prof. E. J. Garwood (9), who contributed a careful discussion of the evidence bearing on the period of intrusion.Teall's great paper closely followed on one devoted to some of the dikes of the north of England (3), and in it he drew attention to the remarkable petrographical Similarity between the rocks of the Heft and High Green dikes and that of the Whin Sill (4, p. 656).

The suite of dikes that forms the subject of this paper is bounded on the south from Sleights Moor (south of Whitby) to Dalston (south of Carlisle) by the well-known series of dikes known collectively as the Cleveland-Cockfield-Armathwaite dike, and on the north by the nearly parallel and more continuous Acklington dike which stretchesfrom Bondicarr near Coquet Island across the southern margin of the Cheviots into Scotland.

In a recent paper by Dr. W. F. Fleet and Dr. F. Smithson attention was drawn, to the occurrence of dark apatites and apatitcs with dark cores of inclusions in certain sediments of the Midlands of England, and it was pointed out that the only other definite occurrences known of these peculiar apatite grains in either igneous or sedimentary rocks appeared to be restricted to the Old Red Sandstone of the Cardiff area, the ‘newer’ granites of Jersey, and the Leinster granite. These writers also expressed the hope ‘that any future observation of such grains may be recorded with a view to tracing the source of the detrital grains of Welsh and English rocks’.

The ‘Whin Sill’ of the north of England is a classic example of an igneous intrusive sheet. A detailed account of its general tectonic and petrographic features has been the subject of a recent; paper by A. Holmes and H. F. Harwood. The present author has made the attempt not so much to give a complete account of the petrology of the Whin Sill, as to describe certain peculiar developments within its mass, such as the coarse-grained bands, acid segregations, &e.

The collection of Hawaiian fungi, of which the material discussed in this paper forms a part, was made by the writers during the winter of 1927-1928. The work was financed chiefly by the United States Department of Agriculture; assistance was also given by the Pan Pacific Research Council. We were aided in our work in one way or another by representatives of every scien? tific institution in the Islands, indeed, by almost every botanist. It would be a pleasure to acknowledge the assistance thus rendered by mentioning each of these friends, but the list would be a long one and could be more conveniently obtained by referring to a list of the members of the Botanical Society of Hawaii. Several years will, of course, be needed for working up the large quantity of fungi collected, even though many specimens have been referred to various specialists. It consequently seems wise to publish parts of the work as completed and to summarize with a final list.

The orientation of the ‘rhombic section’, the composition-plane of the pericline twin, in the plagioclase felspars as an index of the chemical composition of the felspar waJ first utilized by G. yore Rath, who measured the gngle a on the face (010) between the trace of the composition-plane and the edge [010,001]. Duparc and Reinhard, in their comprehensive work on the determination of the plagioclases, quote two series of values for this angle, one due to Wiilfmg and the other to Becke. They comment on the discordance between the two series, most marked at the acid end, and add that they did not then possess suitable material for critical determinations on their own account. Wülfing's values are given in the form of a curve based on data assembled by Schmidt, and those of Becke were first given in a paper on the felspars in crystalline schists.

The discovery of homothallism and heterothallism in the Mucorales by Blakeslee (2), in the Eubasidiomycetes by Kniep (8), Mlle. Bensaude (1), andothers, in the Rusts by Craigie (3), in the Smuts by Hanna (6), and others, and in the Ascomycetes by Dodge (4), Edgerton (5), etc, has led the writer to undertake further studies in the Ascomycetes. This paper presents some work that has been done on a few coprophilous Ascomycetes. Single spore cultures were made in all cases and matings in all combinations were employed in the study of the sexuality of these fungi. The cultures were all grown on agar in petri dishes at room temperature. Single spore cultures were obtained by a dry needle method similar to that described by Hanna (7). It was found helpful in germinating the spores of Ascobolus to treat them first with a warm solution of dilute HC1 for five or ten

The present paper summarizes the facts at present known regarding a characteristic effect that is often produced in the fresh plagioclase felspars of igneous rocks by thermal metamorphism—namely the development of a special type of cloudiness caused by the appearance of minute inclusions. Reference is also made to certain wel|-known rocks in which the clouding of plagioclase felspars has been described without any suggestion that the peculiarity of the felspars is connected with thermal metamorphism.

In the Mineralogical Magazine for September, 1930, Dr. Frederick Walker describes 'A tholeiitic phase of the quartz-dolerite magma of central Scotland'. Several pages of the article are devoted to a consideration of the phenomena he has observed in these rocks in their bearing upon certain views which I have expressed. In most respects Dr. Walker has clearly grasped the essential features of my thesis, and his efforts to obtain further information on the various points have been well directed. I am glad to welcome such a discussion as he has given, even though his conclusions are somewhat opposed to mine. In one respect, however, he has apparently overlooked an essential feature of my argument. On this matter, and on some points of evidence given, I should like to present some discussion. I desire also to examine certain other recent papers by Daly and Barth and by Bowen, Schairer, and Willems, in which the views expressed in my article have met with some criticism.

By checking these specimens with the numbers and dates given in Arthur's paper, it was found that many were duplicates of those already studied. In most instances all data except num? bers and date of collection were missing. S. F. Blake identified many of the hosts and others were determined from the rust present. The interesting rust on Senecio sp. was found by S. F. Blake while examining some specimens of plants from Venezuela. Specimens of the two new species have been sent to Dr. Arthur and he also believes them to be undescribed.

In this paper forty species of aquatic Phycomycetes are described from the vicinity of Cold Spring Harbor, Long Island, New York.Of these fungi, fifteen appear to be reported for the first time in ...

This paper deals with some of the names that have been applied to certain lignicolous and corticolous Hysteriales. The eleven genera mentioned below were considered by Hohnel (3) to constitute the ...

Follicular Hormone IN a paper published recently by Butenandt and his co-workers,1 the hypothetical formula (I) was developed for the follicle hormone. This formula attempted to correlate the X-ray measurements of J. D. Bernal,2 which made a three-ring system for the hormone probable, with the chemical evidence at that time in hand.

A recent account of pseudo-meteorites by Dr. L. J. Spencer includes a description of nodules of pyrite ‘popularly thought to be “thunderbolts”’. Dr. Spencer himself collected in 1931 a large number from the Lower Chalk outcropping on the foreshore below ‘The Warren’ at Folkestone, Kent. Some of these show well-developed octahedra 5 to 10 ram. across on the outer surface, undoubtedly to be referred to pyrite. More commonly the nodules exhibit small distorted octahedra which might easily be mistaken for marcasite. Indeed, in the past, many of these nodules from the Chalk at Folkestone and elsewhere, have been named marcasite, and they were so labelled in the British Museum collection. Dr. Spencer, therefore, suggested that modern methods should be applied to those cases where the crystalline form is distorted or shOt sufficiently developed to serve as a means of distinction between pyrite and marcasite. The methods suggested in his paper are (1) X-rays, (2) polarized light reflected from polished sections of nodules.

This paper presents a taxonomic study of Septonema toruloideum Cooke & Ellis and the cultural evidence which establishes this long-known but seldom reported Hyphomycete as a stage of the recently d...

This paper reports the discovery of the genus, Itajahya, in North America, discusses the genus, gives a description of the North American plants and records data on their distribution. While on a collecting trip during September, 1941, through the arid regions of Arizona and New Mexico, we found a phalloid which at a casual glance seemed to be a white form of Phallus impudicus; hence no special effort was made to collect many specimens. Later a closer study of the plant showed that it was not P. impudicus, but a form unknown to either of us. A special search was then made for as many specimens as we could find. We decided that it might be an Itajahya, but it seemed improbable that a tropical, wet climate plant could grow under such arid conditions.

In this paper eight species are described as new and three new combinations are proposed. Sixteen species are listed as new to Oregon, and ten new to America are as follows: Galerula pygmaeoaffinis (Fries) Zeller, Hypholoma dispersum Fries, Lactarius obnubilus (Lasch) Fries, Lepiota rhacodes (Vitt.) Fries, Naucoria escharoides Fries, Pleurotus limpidus Fries, Psalliota augusta Fries, P. dulcidula Schulz., Stropharia psathyroides Lange, and Tricholoma amplum (Pers.) Rea. Types of the new species are in the Oregon State College Herbarium. Ridgway (10) was used as a color standard in the descriptions of new species. 1. Amanita muscaria Fries.

The studies reported in this paper were made as opportunities and materials offered during the course of investigations of the leaf rust of the grasses, the results of which have been given elsewhere (1933). A number of the cultures were made possible through the kindness of the late Mr. E. Bethel, to whom the writer is specially indebted for material and clues concerning connections based on his discriminating field observations.