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Summary Using a more sensitive fluorimeter than has previously been described in this country, a method is given for estimating riboflavine in malted preparations which gives much better agreement with microbiological assays than had previously been obtained. These preparations when oxidised with permanganate during the purification procedure exhibit a non-specific blue fluorescence which interferes with the fluorimetric assay. In old samples of malt extract this blue fluorescence is quite marked before permanganate treatment. The behaviour of the fluorescent substance with Florisil and its low solubility in chloroform show it not to be lumichrome. It is most effectively separated from riboflavine by adsorption on Florisil and careful elution with 1 per cent. pyridine, the process being observed continuously under the ultra-violet lamp. Spectroscopic studies indicated Wratten 47 as a satisfactory primary filter. Comparison of fluorimetric and microbiological results confirmed this. When calculating the results of riboflavine fluorimetric assays a method based on the assumption that the net fluorescence is proportional to the concentration, and using solvent blanks to determine the net fluorescence, is preferable to the method more usual in this country of using calibration curves obtained by plotting gross fluorescence against concentration. We are indebted to Mr. E. J. Bowen, F.R.S., for advice, to Miss Janet Horsford and Mr. R. Evans for technical assistance, to Mr. G. Slaughter for the fluorescence spectrum of riboflavine, to Messrs.*** Hilger and Watts, Ltd., and Messrs. Kodak, Ltd., for data on the transmission of filters.

Slocan City mineral deposits are "dry" fissure types (Cairnes, 1934, p.114) consisting of high grade silver veins in quartz, with minor amounts of lead and zinc. These veins, almost all in Nelson plutonic rocks, occur in an area of approximately 100 square miles along the eastern margin of Slocan Lake. Mineralogical analysis revealed a definite concentric zoning in the camp; a pyrite halo with high gold values surrounds a core of galena and sphalerite with high silver values. The most commonly occurring minerals in order of deposition are: pyrite, sphalerite, chalcopyrite, gold, tetrahedrite, galena, silver, ruby silvers, and argentite. Quartz is the dominant gangue mineral, with small amounts of calcite, siderite, barite, and fluorite generally concentrated in the central zone. Publically available production data for 73 mineral deposits, and geological and mineralogical data obtained from field and laboratory studies,were organized in a computer-processible data file. Methods used to investigate the usefulness of such a file for both academic and practical purposes include: computer generated plots and contour maps, correlation studies, trend surface analysis, multiple regression, and chi square analysis. Computer contour plots and trend surface analysis were rapid means of analyzing lateral zoning of average metal grades and ratios. Patterns obtained substantiated the mineral zoning which was based on data from appreciably fewer mineral deposits. Multiple stepwise regression showed that value of a deposit (estimated by total production in tons) is dependent on average grades of lead and zinc, and volume percentage total sulphides. Consequently, the tonnage potential of a prospect might be predictable within specified limits from a single bulk sample and a brief geological examination. Chi square analysis showed that relatively large deposits are characterized by a more-or-less northeasterly strike and the presence of small amounts of barite and carbonate gangue. The ease and rapidity with which proven statistical techniques can be applied to the mass of informal ion in a computer-processible data file gives great scope and practicality to the concept.

Frederick W. Simms

ed. by F.W. Simms, Handschriftliches Exlibris: "G. Albert Escher. Felsenhof" 990022005540205503_0001 Exemplar der ETH-BIB

A few months ago I had the pleasure of presenting to the Geological Society some fossils collected by me in the course of the construction of the Bletchingley Tunnel, upon the line of the South Eastern Railway. These fossils consisted of bones of the Iguanodon, Lepidotus Mantelli , and five specimens of the plant Clathraria Lyellii . I now request the Society9s acceptance of a fine specimen of the Lepidotus Mantelli , which was found in the excavation about two hundred yards from the western extremity of the tunnel. The range of hills formed by the escarpment of the lower green sand extends between Red Hill and Tilburstow Hill, and its direction is nearly from west to east. Between Bletchingley and Tilburstow Hill, this range sends off a spur in a southerly direction. It was through this spur, in a line nearly parallel to the sand range, and about a mile to the south of it, that the railway tunnel, and the excavation at each end, were carried. The spur, in the line of the cuttings, consisted chiefly of Weald clay. It was proved by the railway cuttings that this spur formed part of an anticlinal axis, which, as far as I can judge, extends across the Weald from the chalk of the North Downs in Surrey, between Merstham and Grodstone, to the chalk of the South Downs in Sussex, near Ditchling.