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In a previous paper (‘Philosophical Transactions,’ A, 1897, vol. 189, p. 137) we have drawn attention to the fact that the disturbance set up in a liquid by the impact of a rough sphere falling into it, differs in a very remarkable manner from that which follows the entry of a smooth sphere. In the present paper we describe further experiments, made with the object of ascertaining the reason of this difference, and give the conclusions reached. It appeared desirable, in the first place, to take instantaneous photographs of the disturbed liquid below the water-line. These were easily obtained by letting the splash take place in an approximately parallel-sided thin glass vessel (an inverted clock-shade) illuminated from behind. The liquid surface when undisturbed was about level with the middle of the camera-lens, which was focussed for the sphere when under water. The general arrangement of the optical apparatus will be suffi­ciently understood from the accompanying cut (fig. 1). The method of timing the illumination was that already described ( loc. cit. ).

Attention is drawn to the greater optical uniformity of filter paper by reflected light than by transmitted light. The relative merits of employing reflected light and transmitted light, both on dry and transparent paper, are considered from the standpoints of ease of calculation, instrumental convenience and error. Under the conditions described here, in which an aperture of only 3 mm × 3 mm is used, the reflection method on dry paper is recommended. Measurements may also be taken on transparent paper. This causes an increase in error when transmission is used, but decreases the error when reflection is used.

The collection efficiency of nine types of filter papers for air sampling was determined for monodispersed polystyrene latex aerosols by using a forward light scattering photometer. The aerosols were 0.091, 0.198, 0.365, 0.500 and 1.099 mu m in dia., which flowed through a test filter paper at a face velocity from 4.2 to 200 cm/sec. Toyo No. 660, No. 60 and No. LP filter papers exhibited minimum efficiencies at the face velocity range between 10 and 80 cm/ sec, and in the particle size range between 0.1 and 0.5 mu m. The collection efficiencies of Toyo No. 5A and Whatman No. 41 filter papers were over 95% for all the particle sizes at a face velocity higher than 100 cm/sec. Toyo HE-40, HV- 70, Toyo GB-100 and Gelman E filter papers showed collection efficiencies higher than 99%. The theoretical filter efficiency based on single fiber filtering mechanisms and the effect of neighboring fiber interference on the collection efficiency are also discussed. (auth)

A theory previously developed by the author to describe the horizontal spreading of liquids in paper has been applied to the case of a liquid rising by capillary action in a vertical strip of filter paper. The phenomenon is complicated by a surface roughness effect which had to be taken into account. The theory leads to simple expressions for the rate of rise and the distribution of liquid which are in agreement with experiment. When gravity can be neglected, the height of rise is proportional to the square root of the time. When gravity is important, the height of rise is a more complex function of time than the simple square root dependence. In addition, the liquid approaches a limiting height.

Reflection factor curves for gaslight photographic papers with matt and glossy surfaces have been obtained for a fixed direction of view of 30°, this direction lying in the plane of incidence. The papers give not only a specular peak, but also a "throwback" peak whose maximum occurs when the directions of incidence and view coincide. The height of the throwback peak is related to the reflection factor of the paper at the angle of the throwback peak by a linear law. By considering in turn the different components of the photographic paper, the throwback peak has been shown to have its origin in the baryta layer. The complete reflection factor surfaces for a fixed direction of view of 30° have been built up for two pieces of matt surface paper from the reflection factor curves in different planes. As various liquid suspensions also give a throwback peak, the peak may have its origin in some kind of scattering effect.

Pressure pulses of 8.2 × 107 dyn cm-2, each lasting for about 0.01 sec, were applied to paper, and the scattered light from it was measured simultaneously in order to study the response of pores in paper under dynamic conditions. During the compression phase the deformation in pore surface, i.e. the loss in fibre-air interface, is found to be linearly related to the square root of pressure, and the minimum pressure required to compress a paper to the non-porous state is estimated to be around 5 × 108 dyn cm-2, depending on the type of paper. The decompression curve, however, always follows a different path; thus, a cycle of compression and decompression shows large hysteresis. An approximate calculation is made of the energy loss per cycle, and this shows the associated temperature rise to be less than 1 degc. The delayed recovery from compression is large compared with the elastic recovery, but the permanent set is very small. Both the resistance of pores to compression and the energy loss per unit volume seem to be related to the paper density.

A new technique for measuring peak pressures of repeated high amplitude sound pulses in liquids is described. The method involves the transfer of carbon from carbon paper to white `printing-out paper' as a result of the pressure exerted by a pulse. The darkening produced on the white paper was estimated photometrically and used as a measure of the peak pressure in the pulse. Using this procedure, measurements were made in a water column of pulse peak pressures up to 700 atm.

Deposits of coal dust collected on filter paper from airborne clouds have been studied in connexion with their light screening power. This depends on the nature of the paper as well as the size and concentration of the particles. Nine kinds of paper were investigated, two of them in detail. Some idea has been obtained of the qualities necessary in a filter paper in order that the dust deposits will have maximum optical density. Theoretical expressions are derived for light screening according to how the particles are dispersed in the paper. Maximum screening would result if each particle shadowed individually, but this is only possible in very sparse deposits; otherwise, overlapping of the particles has to be allowed for. Diffraction of light by the particles and the effects of diffusion of light in the paper are discussed.

A method is described for the Spectrochemical analysis of samples in solution form, using a rotating filter disc for carrying the solution into the analytical gap. Results are given of a statistical comparison with the coated-electrode method.

A description is presented on a nonrecording densitometer for photometry of electrophoregrams in passing light. The instrument may be easily made in any biochemical laboratory with the aid of available parts; the parts may be replaced by analogous ones without impairing the quality of the device. A method is presented for tracing the curve of the optic density and for calculation of the ratio of the fractions of the mixture studied.

Frozen sections are cut from the specimen until the level of interest is reached. A strip of paper (bond or similar writing paper) 5 cm long and about 1 cm wider than the specimen is moistened with water, closely applied to the surface of the specimen and frozen onto it. As the section is cut, the end of the paper strip above the knife is grasped and turned backward toward the other end of the strip. The section is then applied to an albumenized glass slide, firmed and thawed by finger pressure, and the paper removed. After thorough drying, the preparation is ready for further processing. When properly performed, mounted sections whose details coincide to those of the uncut block can be obtained. If thawing on the knife is prevented by cooling the knife, the technic can be performed without a cryostat, but it is also feasible to use a cryostat if a favorable temperature is maintained. The authors obtained 30 μ serial sections, suitable for stereotaxic mapping, from rabbit brain by this method.

This short paper describes a proposed structure of a broad-band electrooptical modulator and an application of existing microstrip analysis programs to determine dimensions of the structure for a broad-band property. Results of numerical computations indicate that it is possible to obtain a broad-band modulator by using LiNbO/sub 3/ or LiTaO/sub 3/.

A graph paper on which a Gaussian function of unit amplitude appears as a straight line was produced in an attempt to devise a method which would combine the obvious advantages of a linear presentation with the improved definition and convenience of a differential plot. A semilogarithmic plot of the linear differential pulseheight spectrum of 622 kev gamma ray from a Cs137 source is given as an example of the technique. The method requires only the data points from the multichannel analyzer and an estimate of the maximum height of the photopeak above background. Gaussian plots proved convenient checks on instrumental reliability; amplifier nonlinearity or drift cause noticeable deviations from linearity. (P.C.H.)

ELECTROPHORESIS and ionophoresis on paper are being widely used, and a number of different forms of apparatus for carrying out this technique have already been described. The purpose of this communication is to give further details of an apparatus already briefly described1, which has been used for a considerable time with satisfactory results. While we do not claim that it is superior to other types of apparatus, it has the advantage of simplicity, results are reproducible, and the movement of a given substance varies linearly with time. The cross-section is shown in the accompanying diagram. The apparatus consists of a flat rectangular glass tray in which stands a closely fitting glass frame which carries the paper strip and rectangular ‘Perspex’ electrolyte boxes. The dimensions of the apparatus are not critical, but glass drip-trays from refrigerators are very convenient, the outside measurements being about 35 cm. × 20 cm. × 5 cm. The frame is constructed of two rectangles of glass rod, mounted one over the other, and separated from each other by about 1.5 cm. by means of sealed-on pieces of glass, or by pieces of cork at the corners. The frame stands on short legs to keep the paper away from the floor of the tray. Each electrode box has a hole drilled through the end about 1 cm. above the bottom. This enables electrolyte-levels in both boxes to be balanced prior to electrophoresis, and also permits old electrolyte to be run out and replaced by fresh, should this be desired.

Publisher Summary Nucleic acid components on paper chromatograms are photographed by making a contact print by filtered ultraviolet light onto sensitized paper through the dried paper chromatograms. In the procedure, the source of ultraviolet light is a Hanovia Homesun lamp, a 450-watt, 200-volt, mercury arc lamp. This is used in conjunction with a specially constructed filter. Various sensitized papers used for making contact copies of printed pages are suitable for the present purpose, for example, Kodagraph Contact Standard. Time of exposure and distance of paper from the light source are determined with known standards. For making the prints, it is quite satisfactory to pin the chromatogram paper over the photographic paper on a planoconvex wooden surface. A piece of plywood is fastened to a board with a small strip of wood under the center to bow the plywood out a little. After development, the paper is fixed and washed in the usual way.

ESTIMATION of microquantities of purines by paper chromatography was first suggested by Hotchkiss1. Later, detection by photographing with an ultra-violet source has amplified the method2. Tennent et al. 3 and others have designed adaptors for the Beckman spectrophotometer to enable direct estimation of the purines from paper chromatograms. This method requires costly instrumentation, and is time-consuming unless an automatic recorder is provided.

VERY recently, Matthias1 has described a modified technique which may be looked upon as a combination of uni-dimensional and circular paper chromatography. In this case, substances to be chromatographed are applied near the edge of a strip of paper, the end of which is made in the form of a cone; thus the substances are at first radially distributed, which results in better separation.

Migration, the movement of one component in a matrix of another, is a phenomenon well known in the paper, plastics, printing and other industries. Because of the thin films generally involved, migration over short distances can result in large changes in certain properties. This paper describes the use of a modified interference microscope to measure adhesive distribution in a layer of pigment coating on paper. The modifications to the standard instrument are described. The technique described allows far greater accuracy and precision in the measurement of phase changes than previous visual methods. It may be readily adapted to the examination of other thin films.

An automatically recording densitometer is described depending on the use of a photomultiplier operated at constant anode current. The application of this instrument to evaluation of electrophoresis data from filter paper strips is discussed. Some advantages of the circuit are outlined.

A form of reflectometer for measuring the show through tendencies of printing papers is described. Its grading of a series of nineteen papers covering a wide range of opacity is in good agreement with the judgment of 173 trade observers. The instrument can also be used for measuring reflexion factors. Diffuse illumination, normal viewing and normal illumination, diffuse viewing can both be used and are shown experimentally to be practically equivalent, but the latter is more convenient. The opacity figures can be converted to the U.S. TAPPI Opacities by means of an equation due to Judd: the results obtained are in good agreement with measurements made on the American Bausch and Lomb Opacimeter.

Measuring principle of Bekk's smoothness is analysed and it is clarified that there exists in measuring Bekk's smoothness excessive leakage of air which depends on permeability of paper and the roughness of paper of the opposite side of the tested surface. And so the excessive leakage is measured experimentally to be found out that it can not neglected for determining surface roughness of paper by Bekk's method.A direct reading instrument of smoothness of paper are designed applying a similar principle of air micrometer. Theoretical and experimental analyses show that a flow of air through spaces between a test surface and a flatly finished surface obeys Hagen-Poiseuille's law. From this respect the relation between a value of Bekk's smoothness and pressure drop of the new instrument can be given theoretically.Experimental researches show that the observations of smoothness of paper, which is obtained by the new instrument, coincide with those of Bekk's instrument when they are corrected by estimating the excessive leakage.

In the above-mentioned paper Mr. Ward communicates theoretical and experimental investigations which, as far as they are correct, are in their essential parts already published, and indeed somewhat more completely in three papers by Gouy and ourselves, the latter investigations having been suggested by Professor Kundt. Experiments on the rotation of the plane of polarisation of light by means of interrupted currents, like those of Bichat and Blondlot, are here excluded. Since the above-mentioned papers have not been noticed by Mr. Ward, and are hence probably not well known, it may be of interest to reproduce here their essential contents.

I have studied the visco-elastic properties of paper by vibrating reed method at super low frequency range and I measured, Youngs modulus internal frictional coefficient (viscosity).Youngs modulus and viscosity varies by direction in hand made paper, but Youngs modulus is independent of frequency in the range of low frequency. It reduces as increasing frequency. This viscosity is so-called apparent viscosity so, I will convert it true viscosity by next method let us shearing stressv2lv : frequency, l : length.rate of shear v2l/η I plot v2l, v2l/η I obtain consistency curve.I will regard consistency curve as two kinds straight line.I think this straight line means the true viscosity. Let us those viscosities ηHF (Viscosity at high frequency) ηLF (Viscosity at low frequency). Reasonable solution of these two kinds viscosity ηHEηLFis the problem of future.Youngs modulusEand ηHF, ηLFincrease as reducing its freeness in hand made paper.but increasing process changes by pulp sorts.

The Barkas analysis is applied to a series of nine papers of known visual gloss. With some reservations, the analysis is found to hold approximately and the distribution of mirror facets so derived is found to accord well with the surface structure of the papers as found by microscopic examination. It is concluded that, whilst the analysis is of negligible value for practical gloss determinations, it appears to present a useful method of investigating the surface structure and "finish" of paper and similar delicate materials. The gloss of the papers examined appears to be assessed solely by the intensity of the light reflected at the specular angle and not by the contrast noted by examination at different angles nor by the ratio of specularly-reflected to diffusely-reflected light. Some suggestions for future research are given.

It is established that when a uniform film of liquid is pressed against the surface of a material through rolling, the depth of the deepest part of surface which can be coated is equal to the initial thickness of the film. The total coated area, which may be determined by the change in diffuse reflectance of the material, varies with film thickness but is shown to be independent of the rheological properties of the liquid. These observations are utilized in a treatment developed to determine the topographical structure of a surface. Results show that the surface structure of paper can be described by the Gaussian distribution of the logarithm of depression. The surface structure is sensitive to both load and velocity of rolling, but tends to become stabilized at high load or low velocity. It is suggested that the maximum of the pressure distribution in rolling matters most, but its effect may be complicated by the varying number of stress-bearing sites on the surface and by the interaction between them and their neighbours. The effect of velocity is attributed primarily to the viscoelastic nature of paper and secondarily to the number of stress-bearing sites.

When ink is applied to a paper surface from a smooth plate the area which becomes coated is well known to depend on the thickness of the ink film on the plate. A simple, two-parameter relation has been found which describes this dependence, and it has been shown that this effect provides a convenient method of determining the topography of the surface of a paper. A treatment has been developed whereby the frequency distribution of the depth of depression in a paper surface can be determined by measuring the areas covered with ink when films of different thicknesses are applied. The area coated may be measured directly or found by observation of the diffuse reflectance of the printed paper: an equation is derived whereby the distribution of depression can be calculated to a reasonable accuracy from measurements of the diffuse reflectance. Typical distribution curves obtained by this method show maxima near the shallow end - at about 0.2 μm for coated papers and at about 1 μm for newspapers.

A versatile automatic scanner for paper strips which records directly optical density or radioactivity is built around a servo type recorder (Brown). Interference filters provide a narrow band light source. For scanning in the visible or ultraviolet where monochromatic light is desired the monochromator of a Beckman model DU spectrophotometer replaces the filters. The instrument incorporates positive synchronization of strip and recording paper, sequential scanning of strips to provide an optical density curve followed by superposition of the integral of this curve. Areas are easily calculated without the need for planimetry. The slits of varying size are interchangeable and are designed for either optical or radioactive scanning. For medium levels of activity a Geiger‐Muller tube is interchangeable with the photocell, while for low activities, optical scanning of autoradiographs may be performed.

Direct exposure to the sunlight causes Japanese-paper to deteriorate its physical qualities.This deterioration appears after about 100 hours' direct exposure.(1) Strength, elasticity and other qualities are weakened.(2) In case of whether bleached or unbleached, the latter are more affected.(3) Elasticity is particularly weakened by exposure.(4) Breaking-length is bigger by 100-200 hour's exposure than by 0-100 hours' exposure.(5) Diffractiveness is remarkably lessened by exposure.(6) Gampi-paper becomes fragile in particular by the sun-light.

Hmax and smoothness were measured by needle touch type unevenness tester and Bekk automatic smoothness tester, respectively, and relation between h and Hmax or smoothness was examined.It was found that h was closely conected with Hmax or smoothness.When thickness of paper was measured in superposition by micrometer, and h was obtained with the formula showed in part 1, thereby the surface condition of paper is briefly known.

The performance of the Bausch and Lomb and Sheen glossmeters is examined. Comparison of gradings of nine printing papers according to visual and instrumental means shows that, despite high correlation between them, there are nevertheless important discrepancies not attributable to sampling, instrumental or personal errors. The effect of angle of incidence and viewing on grading is investigated; best results are noted at 45°, and the discrepancies become more pronounced at greater angles. Gradings of the same papers according to the Jones, Askania, Goerz, Ostwald and Klughardt methods are examined; all are found unsatisfactory. It is concluded that, for the limited range of papers tested, the most satisfactory grading is given by measurements of the intensity of light received when angles of incidence and viewing are 45°.

When the intricacy of the subject, on which my two last papers have been treating, is considered, it will not appear singular that a few supplementary articles should be given. The compression of the account of the experiments into a small compass, where many material circumstances must be left unnoticed, may throw some obscurity on the results, which can only be removed by examining the subject in a fuller ex­tent, and from various points of view. I hope the following illustration and additional explanations will have the effect of clearing up what may possibly to some appear obscure or doubtful, in either the first or second part of my paper, and serve also to make the conclusions, which in the second have been chiefly supported by prismatic experiments, directly applicable to such as have in the first been made by convex glasses. That the colours in all prismatic phenomena, which have been examined in the 44th, 45th, 46th, 47th, and 48 articles of my paper, are produced either by the interior critical separa­tion arising from the different reflexibility of the rays which cause the blue bow, or by the exterior critical separation arising from the different intromissibility of the rays which cause the red bow, has been so clearly and circumstantially proved that it can admit of no doubt; it may even be con­ceived by some that I have been too particular in giving the precise angles, when we see in the LectionesOptica , Sect. II. Par . 2, page 257, 258, how far Sir I. Newton has explained the blue bow ; but a sufficient reason for this minuteness was to give greater clearness to my explanation of the new pheno­menon of a red bow, which I have with equal precision de­scribed, and which by this means may be, step by step, compared with the production of the blue bow; but a sufficient reason for this minuteness was to give greater clearness to my explanation of the new phenomenon of a red bow, which I have with equal precision described, and which by this means may be, step by step, compared with the production of the blue bow. By this precaution I hoped to anticipate any objection that might occur, such as, for instance, that Sir I. N ewton has also explained the red bow which (it may be supposed) merely the converse of the blue bow. This conception, although N ewton no where speaks of a red bow, seems to be countenanced by what is said after he has shown that the blue bow is caused by the different reflexibility of the rays of light; for as he affirms that the red, orange, and yellow colours are transmitted, he contrives a method of proving it experimentally, by adding a second prism, placed under that which gives the blue bow, and thus making the transmitted rays visible. The full import of this Newtonian experiment will be considered in the following articles.

For a range of papers of luminance factor varying from 20% upwards and of gloss varying from almost complete matt to gloss high enough to give fair mirror images the equation G = S(a + 10/L) is proposed, where G is a measure of visual gloss, S is the relative intensity of reflected light under 45° - 45° conditions of illuminating and viewing, L is the luminance factor expressed as a percentage and a is a constant which, under the conditions used by the authors, is approximately 0.20. The visual gradings of eight papers out of ten are not markedly affected by the conditions of observation, but for the remaining two there is a highly significant shift in grading according to whether these conditions permit formation of mirror images or not. Gloss is considered to be a gestalt, corresponding to no single physical property of a surface, being judged by appraisal of a physical situation taken as a whole. The validity of the method used in establishing the psychological gloss scale is checked by experiments in weight grading.

By the use of Micro-Interferometer Niodel MI, the features of smoothness for various coated papers are observed. These features seem to closely relate with the visual degrees of smoothness of papers.Samples used are varnished art papers, brushed art papers and east coated papers.

A novel technique for the color visual display of two-dimensional electrostatic fields is described. Temperature-sensitive encapsulated liquid crystals in sheet form are bonded to carbon-impregnated conducting paper on which a prescribed electrode configuration has been painted. The joule heating of the conducting paper creates a non-uniform two-dimensional temperature field to which the liquid crystals respond with color changes. Bands of uniform color identify isotherms which under certain conditions correspond to lines of constant electric field magnitude. The technique is applied to the study of various problems in electrostatics and potential fluid flow.

The surface color of paper changes depending on observed angle. Such variations in surface color and their relationship to gloss are examined with the aid of a goniophotometer equipped with an interference filter. The results obtained are as follows:1) The smoother the surface and the more uniform the orientation of the constituent fibers of the sample, the closer the chromaticity coordinates get to the light-source color on the chromaticity diagram, when the sample is measured in a specular reflection direction.In other words, the larger the amount of specular reflection light in the goniophotometric reflection curve, the closer the chromaticity coordinates get to the light-source color on the chromaticity diagram.2) The larger the incidence-receiving angle, the larger the tristimulus values is, when the sample is measured in the direction of specular reflection. When the sample has a rugged surface, the angle which shows the maximum quantity of reflection light may deviate toward the direction larger in angle than the direction of the specular light. In this case, when the sample is measured by a goniophotometer at an angle showing the maximum quantity of reflection light, it shows the maximum tristimulus values.3) The goniophotometric color measured is shown by color mixture between the lightsource color and the object color on the chromaticity diagram.4) When the incidence-receiving angle of a paper is changed, its tristimulus values vary, resulting in color differences.5) When gloss is measured in the direction of specular relation, the angle showing the maximum quantity of reflected light may deviate toward a direction larger in angle than the direction of specular light. It is, therefore, recommended that the gonio-photometric reflection curve of the sample is measured before gloss is examined.

The effect of ohmic and dielectric losses, conductor thickness, and frequency dispersion on the performance of edge-coupled microstrip directional couplers and interdigital filters have been determined in this short paper. The odd- and even-mode attenuation constants due to ohmic losses in the conductor have been calculated using Wheeler's inductance formula. The theoretical results for the characteristic impedance and propagation constants are in good agreement with the experimental results of Napoli and Hughes. Among the parameters that can be calculated from this theory are the isolation, directivity, and coupling coefficients of lossy directional couplers and the midband insertion loss of interdigital filters.

Description of a new simple method using Whatman No. 1 chromatographic paper strips and rings for production of standardized corneal burns. Details of the method as well as multiple usage for various

This short paper shows how nonseparable solutions of the Helmholtz wave equation can be used in the synthesis of waveguides and cavities with nonconventional cross section, and also investigates the attenuation and Q factor.

The purpose of this short paper is to construct the dissipation and scattering matrices of lossy junctions in terms of the eigenvalues of the dissipation matrix. This removes the need to rely on inequality relations between the scattering parameters of lossy circulators. The eigenvalues of the dissipation, scattering, and admittance matrices are related. The eigenvalues of the dissipation matrix give the dissipation associated with each possible way of exciting the junction. The ones of the scattering matrix give the reflection coefficients associated with these different excitations. The admittance eigenvalues define in each instance the eigennetworks of the junction. This leads to the definition of the entries of the dissipation matrix in terms of the loaded and unloaded Q-factors of the junction eigennetworks. The scattering matrices of a number of lossy 3-port junctions are also constructed directly in terms of the elements of the eigennetworks.

Research has shown that the determination of absorbed microwave energy as well as the control of environmental parameters are important in relating biological-effect data to, radiation protection. This short paper describes the development of an environmentally controlled waveguide irradiation facility for the exposure of small animals to 2450-MHz CW microwave energy. Integral dose rate is determined without perturbing the microwave field interacting with the irradiated animal.

It is normal practice when designing electrical machines to design for operation within the maximum temperature limits of the insulation. If part of the winding is not effectively cooled under these conditions, the resulting temperature rise can damage the insulation and seriously reduce the length of operational service of the machine. This paper discusses a method of detecting high-temperature regions within a winding and of estimating the ‘hot spot’ temperature. The investigation has been concentrated on the design associated with a direct water-cooled winding, although the results could be applied generally on other electrical machines.