May 6, 1909J 



NA TURE 



299 



years. Two percolation gauges were used, belli of which 

 were exactly a superficial yard in area, and contained a 

 cubic yard of natural soil, one of chalk and the other of 

 gravel. The average annual amount of percolation through 

 the chalk gauge was 10-84 inches, and through the gravel 

 gauge 10-34 inches. The average yearly rainfall was 2546 

 inches. It appears that the rate of percolation is governed 

 by the rate of rainfall, for when once the gauges have 

 brconie sensitive, by being thoroughly wetted, the rate at 

 which rain percolates depends entirely on the quantity of 

 rain immediately falling. The evaporator used for deter- 

 mining the evaporation was a floating copper vessel i foot 

 iTi diameter supported by a life-buoy ring, connected by 

 four arms with the evaporating vessel, the whole being 

 floated in a tank of 4 feet internal diameter containing 

 about -j feet depth of water. The average annual amount 

 of evaporation by this gauge was 18-14 inches, and the 

 average amount of condensation was 0-36 inch. — The 

 meteorological conditions in the Philippine Islands, igo8 : 

 Rev. JosiS Algue. The year 1908 was one of extra- 

 ordinary meteorological conditions. Heavy floods occurred, 

 and frequent violent cyclonic storms passed over or affected 

 the archipelago. The author stated that out of the four- 

 teen typhoons of extraordinary intensity which have 

 occurred during the past twenty-nine years, five occurred 

 in the year 1908, the most violent being those of .Sep- 

 tember 23, October 13, and December "5. It seems that 

 (he part of the archipelago which is visited the most fre- 

 quently by these, extraordinary typhoons is the northern 

 p.ut of Luzon from the parallel 11;° 30' to the Batanes 

 Islands, and from parallel 11° to 14° N. 



Mathematical Society, Apr 1 22. — Sir W. D. Niven, 

 president, in the chair. — The principles of the general 

 theory of integral functions : F. Tavani. — The equations 

 of electrodynamics and the null influence of the earth's 

 motion on optical and electrical phenomena : H. R. Hasse. 

 — .Solution of a certain transcendental equation : G. N. 

 Watson, — Physical applications of certain conformal trans- 

 formations of a space of four dimensions and the repre- 

 sentation of a space time point by means of a sphere : 

 11. Bateman. — Some criteria for the residues of eighth 

 and other powers : k. V.. Western. — Discontinuities of a 

 function of one or more real variables : Dr. \V. H. 

 Young:. 



Institution of Mining and Metallurgy, Apiil 22. — Mr 

 Edgar Taylor, president, in the chair. — The valuation of 

 mining areas on the Rand : W. Fischer Wilkinson. In 

 this paper the author points out that, to calculate the 

 most suitable rate of working for any given area, it is 

 necessary, in the first place, to make an estimate of the 

 probable tonnage and the value of the ore, and that then 

 the problem is to be solved in accordance with the follow- 

 ing elements : — capital expenditure required for a given 

 production, the available tonnage and its value, the cost 

 of working, and the rate of interest required. On account 

 of the last-named clement, time is the important factor, 

 and the paper proceeds to quote instances of the bearing 

 of this factor on the profitable working of any given 

 property, in the correlation of profit per ton and the suit- 

 able duration of life of the mine. Incidentally, the author 

 is in favour of attacking the rich reefs and the richest 

 sections of the poorer reefs first, in order to give a higher 

 grade during the early years of a mine's life. — The 

 " wholesale " idea in gold mining ; W. R. Feldtmann. 

 The author of this paper is in favour of increasing re- 

 duction plant up to the practicable producing limit of a 

 mine, his claim being that large-scale working is directly 

 conducive to the best economic results, and that it is the 

 maximum total net profit during the life of a mine that, 

 should be striven for rather than low costs or high profits 

 per ton, as the case may be, one of the factors being the 

 reduction of costs per ton and the other the grade and 

 aniiu.-il quantity of ore available, these interacting one on 

 the other. This is illustrated by a series of diagrams, 

 which serve to bear out the author's argument that, on a 

 paying mine, an increase in the tonnage crushed, by 

 additions of ore of a yield grade anything in excess of 

 the " unit charge," will result in an increased annual and 

 total working profit. — The computation of the present value 



NO. 2062, VOL. 80] 



of developed and undeveloped mines : W. H. Goodchild. 

 In this paper the author deals with certain debatable 

 points in the practice 01 computing the present gross value 

 of a mining property, giving instances of the different 

 methods of calculation adopted by various authorities, and 

 the influence produced by the peculiar characteristics of 

 a given mine and its state of development. 

 Paris. 

 Academy of Sciences, April 26. — M. Lmile Picard in 

 the chair. — Invisible pathogenic micro-organisms and the 

 physical proofs of their existence : A. Chauveau. The 

 organism of ordinary vaccine is still unknown ; the effects 

 produced by inoculating with vaccine of gradually in- 

 creasing dilution prove that the virulent agents are con- 

 stituted by independent corpuscular elements, held in 

 suspension in the fluid. That the virus is not of a crystal- 

 line or colloidal nature is shown by the fact that a vaccine 

 covered with water, and allowed to diffuse, does not 

 communicate any virulent properties to the upper layers. 

 The invisible agents of the virulence of vaccine are re- 

 garded as being certainly living beings. — The resinous 

 nature of the bark of Sarcocaulon of the Cape and of 

 .some Kalanchce of Madagascar : Edouard Meckel. — The 

 hydrodynamical conditions of form in fishes : FrM^ric 

 Houssay. A description of experiments on the loss of 

 energy during the propulsion through water of six models 

 of geometrical form. From the results, the form of a fish 

 would not appear to correspond to that of minimum resist- 

 ance ; loss of speed would seem to correspond to a gain 

 of stability. — The photographic determination of the colours 

 of the stars : Oesten Bergstrand. A grating, with bands 

 1-5 mm. in width, was placed before the opening of the 

 telescope, thus producing a series of symmetrically placed 

 diffraction spectra at the focus. By measuring the distance 

 between the two spectra of the first order, the effective 

 wave-length of the light from the star in question could be 

 determined. The results are expressed in a scale in which 



corresponds to a mean wave-length X = 4i9.9 /i/i, and 

 12, A. = 449-6 y-ii.. Stars can be divided into two well- 

 marked classes — white stars (X = 42o ^^) and yellow stars- 

 (A = 440 to 450 iifj.). The qualities of the two groups appear 

 to be quite different, and the transition from the one to 

 the other is sudden. — Congruences of normals and contact 

 transformations : Jules Drach. — The theorem of the exist- 

 ence of implicit functions : W. SteklofT,— Critical 

 logarithmic points : Mme. Valerie Dienes, — A partial 

 differential equation of the hyperbolic type : .A.. Myller, 

 — Hyperelliptic surfaces : M. Chillemi,— Stability and 

 diffusion ; the action of mass. Mechanical analogies of 

 the laws of displacement of equilibrium : C. Raveau.-— 

 Polarisation by lateral diffusion : Georges Meslin, It is 

 known that when a ray of light passes through a column 

 of a transparent liquid^ the light issuing perpendicular to 

 the direction of the ray is polarised. If the liquid con- 

 tains crystalline particles in suspension, the quantity of 

 light issuing laterally is increased, but the proportion of 

 polarised light is diminished. In the present note a. 

 singular exception is described in the case of boric acid 

 associated with a liquid of a refractive index greater than 



1 42 (that of boric acid itself). In this case, the light 

 issuing laterallv is partially polarised, with its plane of 

 polarisation perpendicular to the plane of diffusion. 

 Another anomaly afforded by boric acid is that liquids in 

 which it is a constituent possess spontaneous dichroism. 

 — .\ divergent amplifying microscope : Alphonse Berget. 

 A doubly concave lens is placed between the objective and 

 the eve-piece. The arrangement permits of an objective 

 of longer focal length being employed for a given magnifi- 

 cation. — The evaporation of aqueous solutions : P. 

 Vaillant. The vapour pressure is determined by observ- 

 ing the loss of weight of the solution placed in a fl.at dish 

 on a sensitive balance. — Researches on the density of 

 acetylene : E. Mathias. Details of a scries of observa- 

 t'ons on carefully purified acetylene. The densities of the 

 liquid and vapour were measured at various temperatures 

 between -23-75° ^"d 320.^°- The critical temperature, 

 measured bv the method of S. Young, was found to be 

 ■?7os°. The values are compared with the corresponding 

 figures for carbon dioxide. — Cuprous sulphate : .A. 

 Rccoui-a. Bv working in an organic medium, in the 



