No. 107 1, Vol. 42] 



NA rURE 



43 



Mr. Langley, effect of nicolin on the nervous system of the 

 ficsh-wafer crayfish. 



Mr. Shipley, on a new species of Phymosoma, with some 

 account of the geographical distribution of the genus. 



Mr. Adami, on the action of the papillary muscles of the 

 heart. 



Mr. Harmer, exhibition of specimens of a Land-Planarian 

 {Khynchodemus terrestris, O. F. Miiller) found in Cambridge. 



SCIENTIFIC SERIALS. 



The American Meteorological Journal iox March contains the 

 conclusion of M. Faye's articles on the theory of storms, based j 

 on Redfield's laws. The author maintains that cyclones are 

 descending whirls with a vertical axis, that they originate in i 

 the upper currents of the atmosphere, and follow the course of | 

 these currents. He considers it very desirable that two different 

 modes of drawing charts should be adopted, to distinguish 

 between cyclones and statical depressions to which, in his 

 opinion, the laws of storms do not in any way apply.— Prof. 

 H. A. Ilazen contributes an article on the spectre of the Brocken, 

 and gives a summary of various explanations of the phenomenon. 

 He gives the results of his observations upon a similar shadow 

 seen upon Mount Washington. This number also contains an 

 extract from a paper by Dr. Schenck on the climatic treatment 

 of pulmonary consumption ; the advantages of New Mexico, 

 especially, are pointed out. I 



In the number of the Journal for April, M. Faye com- 

 mences a series of articles on trombes and tornadoes ; he 

 deals principally in this number with the theories of various 

 writers and with descriptions of the phenomenon. — Mr. A, H. 

 Button analyses the laws laid down by Padre Viiies relative 

 to the normal points of recurvature of West India hurricanes. 

 The result of his inquiry is that less than 14 per cent, of 

 the tropical storms o'leyed the laws. — Mr. A. L. Rotch 

 summarizes the proceedings of the International Hydrological 

 Congress held at Paris in October last. The next Congress is ! 

 to be held in Rome in 1892. | 



Depart inent of Agi-iculture, Bulletin No. 4, July 1889 (by 

 authority, Government Printing Office, Melbourne) — This 

 Report embodies the results of State-aided scientific effort which j 

 is intended to benefit agriculture, as we sincerely trust it will. 

 The contents are miscellaneous, although all have direct bearing ! 

 on the theory and practice of agriculture. Reports on horse- J 

 breeding, the needs of plants, irrigation, liquorice, yields of \ 

 milk, vineyards, fruit-culture, Danish dairying, &c., yield a 

 varied diet for the omnivorous reader, and will be of special ^ 

 service to Australian cultivators-. We plead guilty to a feeling 

 in connection with the perusal of .such Bulletins as this, that the 

 work is official, and lacks spontaneity. There is, notwilhstand- | 

 ing, much that is valuable. Take, for example, the raisin industry j 

 (p. 91). Here we find described the conditions for successful j 

 growth, varieties, culiivation, and drying. What can be more 

 useful to a colonist up country than to possess trustworthy informa- 

 tion in detail on such a subject ? If he is engaged in the wider 

 pursuits of horse or cattle ranching, he will find subject-matter — 

 addresses of breeders, names of sires, and other information of 

 solid value. The Bulletin will also be of interest to the in- j 

 creasing class of owners of land in Australia who reside in j 

 England, as well as to young men who are thinking of making 

 Austrclia their home. Anyone writing for this class of in- 

 formation should secure the previous numbers and also the future 

 issues, and these he would probably be able to obtain free of 

 charge by application at the offices of the Agricultural Depart- 

 ment at Melbourne, or in London, at the Australian Colonial 

 Offices in Victoria Street. 



SOCIETIES AND ACADEMIES. 



LONDOV. 



Royal Society, March 27. — " Measurements of the Amount 

 of Oil necessary in order to check the Motions of Camphor 

 upon Water." By Lord Rayleigh, Sec. R. S. 



The motion uj^on the surface of water of small camphor 

 scrapings, a phenomenon which had puzzled several generations 

 of inquirers, was satisfactorily explained by Van der Mens- 

 l)iugghe {Memoirc^ Couronnis (410) of the Belgian Academy, 

 vol. xxxiv. , 1869), as due to tt e diminished surface-tension of 

 water impregnated with that body. In order that the rotations 

 may be lively, it is imperative, as was well shown by Mr. 



Tomlinson, that the utmost cleanliness be observed. It is a 

 good plan to submit the internal surface of the vessel to a pre- 

 liminary treatment with strong sulphuric acid. A touch of the 

 finger is usually sufficient to arrest the movements by com- 

 municating to the surface of the water a film of grease. When 

 the surface-tension is thus lowered, the differences due to varying 

 degrees of dissolved camphor are no longer sufficient to produce 

 the effect. 



It is evident at once that the quantity of grease required is 

 excessively small, so small that under the ordinary conditions 

 of experiment it would seem likely to elude our methods of 

 measurement. In view, however, of the great interest which 

 attaches to the determination of molecular magnitudes, the 

 matter seemed well worthy of investigation ; and I have found 

 that by sufficiently increasing the water surface the quantities of 

 grease required may be brought easily within the scope of a 

 sensitive balance. 



In the present experiments the only grease tried is olive oil. 

 It is desirable that the material which is to be spread out into 

 so thin a film should be insoluble, involatile, and not readily 

 oxidized, requirements which greatly limit the choice. 



Passing over some preliminary trials, I will now describe the 

 procedure by which the density of the oil film necessary for the 

 purpose was determined. The water was contained in a sponge- 

 bath of extra size, and was supplied to a small depth by means 

 of an india-rubber pipe in connection with the tap. The 

 diameter of the circular surface thus obtained was 84 cm. (33")- 

 A short length of fine platinum wire, conveniently shaped, held 

 the oil. After each operation it was cleaned by heating to 

 redness, and counterpoised in the balance. A small quantity of 

 oil was then communicated, and determined by the difference of 

 readings. Two releasements of the beam were .tried in each 

 condition of the wire, and the deduced weights of oil appeared 

 usually to be accurate to ^'^ milligram at least. When all is 

 ready, camphor scrapings are deposited upon the water at two or 

 three places widely re<noved from one another, and enter at once 

 into vigorous movement. At this stage the oiled extremity of 

 the wire is brought cautiously down so as to touch the water. 

 The oil film advances rapidly across the surface, pushing before 

 it any dust or camphor fragments which it may encounter. The 

 surface of the liquid is then brought into contact with all those 

 parts of the wire upon which oil may be present, so as to ensure 

 the thorough removal of t>e latter. In two or three cases it was 

 verified by trial that the residual oil was incompetent to stop 

 camphor motions upon a surface including only a few square 

 inches. 



The manner in which the results are exhibited will be best 

 explained by giving the details of the calculation for a single case, 

 e.g. the second of December 17. Here 081 milligram of oil 

 was found to be nearly enough to stop the movements. The 

 volume of oil in cubic centimetres is deduced by dividing o'ooo8i 

 by the sp. gr., viz. 0*9. The surface over which this volume of 

 oil is spread is 



\i: X 84- square centimetres ; 



so that the thickness of the oil film, calculated as if its density 

 were the same as in more normal states of aggregation, is 



o -0008 1 I 63 



= - — -'cm., 



09 X :|7r X 84-* ID'' 



or 1*63 micro-millimetres. Other results, obtained as will be 



seen at considerable intervals of time, are collected in the table. 



A Sample of Oil, somewhat decolorized by exposure. 



