NA TURE 



\ March 26, 1! 



Hinks. Some of the move recent American lamps exhibit 

 decided improvements in the details of construction of the oil 

 reservoirs, the wick-holders and elevators, the arrangement for 

 extinguishing the lamps, &c. 



It does not come within the province of this discourse to deal 

 with the marvellous development of the petroleum industry in 

 America, where the region of Western Pennsylvania now fur- 

 nishes about 70,000 barrels of oil per day, having up to January I, 

 1884, yielded a total of 250,0:0,000 barrels. Nor would it be 

 relevant to enter upon the equally interesting topic of the recent 

 extraordinary progress of the same industry in the Caucasus, 

 which is chiefly due to Messrs. Nobel Brothers, further than to 

 refer to the fact that the Baku petroleum lamp oil, which sup- 

 plies the entire wants of Russia, and is gradually obtaining a 

 footing in Germany, and even here, appears, notwithstanding 

 its comparatively high specific gravity, to be adapted for use in 

 mineral oil lamps of the ordinary construction. This seems to 

 be partly owing to the comparatively small proportion of lamp 

 oil that is extracted from the crude Baku petroleum, in con- 

 sequence of which the variety of hydrocarbons composing that 

 product of distillation which is used for illuminating purposes, 

 presents a narrower range than is the case in the ordinary 

 American petroleum 'oil of commerce. It has also been esta- 

 blished by careful observations which Beilstein has instituted, 

 that some American oil which is specifically lighter than the 

 Baku oil is not so readily carried up to the flame as the latter, 

 by the capillary action of the wick. Mr. Boverton Redwood 

 has carried out some instructive experiments, employing different 

 kinds of wick as siphons, and measuring the quantity of different 

 descriptions of oil drawn over in corresponding periods of time 

 by the different wicks. These showed that the Baku kerosine 

 was drawn over with decidedly greater rapidity than samples of 

 American petroleum of ordinary quality, but that, on the other 

 hand, a sample of American kerosine of the highest quality 

 exhibited a corresponding superiority over the Baku oil experi- 

 mented with. The nature and behaviour of the wick plays a 

 most important part in determining the efficiency and also the 

 safety of a mineral oil or petroleum lamp, as will be presently 

 pointed out. 



Ever since paraffin or petroleum oils, which may be included 

 under the general designation of mineral oils, first assumed im- 

 portance as illuminating agents, accidents connected with their 

 use have continued to claim prominence among those casualties 

 of a domestic character which tend to cast suspicion on the 

 safety of the material dealt with, or of the method of employing 

 it, under the ordinary conditions fulfilled by its careful use. 



The employment as an illuminant of the most volatile portions 

 of petroleum which are classed as spirit or naphtha, has been 

 chiefly limited to the wickless Holliday lamp, in which a small 

 continuous supply to a chamber heated by the lamp flame which 

 surrounds it, furnishes the vapour which maintains that flame, 

 and to the small so-called sponge lamps or benzoline lamps, of 

 which the body is filled with fragments of sponge, and which is 

 intended to be charged only with as much spirit as the sponge 

 will hold thoroughly absorbed ; the small flame at the top of the 

 wick-tube being fed by the gradual abstraction of the liquid from 

 the soaked sponge, by the wick of sponge or asbestos which fills 

 the tube. An ingenious application of naphtha as an illuminant 

 consists in filling a reservoir with sponge fragments kept soaked 

 with the spirit, the vapour of which descends by its own gravity 

 through a narrow tube at the base of the reservoir, and issues 

 from a fish-tail burner under sufficient pressure to produce a 

 steady flame for some time. 



( To be continued. ) 



SOCIETIES AND ACADEMIES 



London 

 Mathematical Society, March 12.-1. W. I.. Glaisher, 

 F.R.S., President, in the chair. — Messrs. Philip Magnus and 

 R. Lachlan were elected Members —Mr. J. J. Walker, F.R.S., 

 made a second communication on a method in the analysis of 

 plane curves. — Mrs. Bryant, D.Sc, read a paper on the geo- 

 metrical form of perfectly regular cell-structure. " Investiga- 

 tion of the properties of the rhombic dodecahedron supplies the 

 clue to the solution of two interesting questions, which are the 

 essential, because the pure geometrical, constituent of several 

 questions as to actual forms in physical nature, such as the geo- 

 metrical structure of compact tissues on the one hand, and the 



geometrical form of the honeycomb cells on the other hand. 

 The first question is as follows : — If space were filled with 

 spheres, and this spacefill of spheres were then crushed together 

 symmetrically till the whole became a solid mass, what shape 

 would each sphere ultimately assume? Since twelve is the 

 number of spheres that can be placed round one sphere, in con- 

 tact with it and with one another, it is evident that each of these 

 ultimate solids would be dodecahedral in shape. The second 

 question is the counterpart of the first : — If space were filled 

 with a homogeneous solid, in which equally efficient centres 

 of excavation were distributed uniformly, what would be the 

 ultimate form of the cells excavated, it being supposed that 

 when the excavators cease their work the walls of the cells are 

 uniform in thickness ? The answer to the first question is mani- 

 festly the answer to this second question also. ' After a geo- 

 metrical discussion the author says : — " We should expect to 

 find this dodecahedral shape in nature wherever originally 

 spherical cells have been uniformly pressed together in a com- 

 plete manner. The condition is probably seldom fulfilled, 

 and examples are therefore difficult to find. We may look 

 for their fulfilment, however, in the centre of a mass of 

 soap-bubbles." The paper then considers the case of the 

 honeycomb cells, with the conclusion : "The above ex- 

 planation tends, however, to show that the bees need not be 

 credited with any economical instinct to account for their work, 

 but only with those simpler instincts, which enable them to 

 carry out a joint work with perfect regularity and exactness, 

 which simpler instincts, while sufficiently remarkable, are fairly 

 within the limits of credibility." — Mrs. Bryant illustrated her 

 remarks with several models of the cube and the rhombic dode- 

 cahedron. — Mr. Kempe, F.R.S., and the President (who stated 

 that he had some few years since considered the matter from 

 another point of view) made some interesting remarks in con- 

 nection with the subject. — Prof. Sylvester, F. R.S., gave an 

 account of a paper on the constant quadratic function of the 

 inverse co-ordinates of « + I points in space of n dimensions ; 

 and Prof. Cayley, F. R.S., and Prof. Hart spoke on the same 

 subject. As the hour was late Mr. Tucker (lion, sec.) merely 

 communicated the titles of papers by Prof. K. Pearson (on the 

 flexure of beams) ; Rev. T. C. Simmons (two elementary proofs 

 of the contact of the "N.P." circle of a plane triangle with 

 the inscribed and ascribed circles, together with a property of 

 the common tangents) ; and by himself (two other proofs of the 

 first part of Mr. Simmons's communication). 



Linnean Society, March 5. — Sir J. Lubbock, Bart., Presi- 

 dent, in the chair. — Messrs. Jas. Epps, Jas. Groves and Wm. Ran- 

 som were elected Fellows of the Society. — Mr. E. M. Holmes ex- 

 hibited a number of new species of British alga;, viz. thirteen from 

 the south coast of England, and six obtained from Berwick-on- 

 Tweed and Fifeshire. He also called attention to examples of 

 the leaves of Eucalyptus Slaieeriana, which are remarkable for 

 their fragrant odour, resembling that of verbena, due to a vola- 

 tile oil which is stated by Mr. Bailey, the Government botanist 

 at Brisbane, to be likely to form an article of commerce in the 

 future. Mr. Holmes also showed a set of plant labels made 

 from the leaves of the Talifat palm. Mr. W. Brockbank ex- 

 hibited a specimen of Lcucojum carpathicum, a variety of Z. 

 vernum, differing from the type by having the flowers tipped 

 with yellow instead of green. The L. carpathicum is said now 

 to be seldom met with in English nurseries. — Mr. C. B. Plow- 

 right showed and made remarks on a Ranunculus infected with 

 spores of Urocystis pomp/wlgodes. — Mr. E. Wethered exhibited 

 some microscopic sections of the " Better Bed " coal-seam of 

 Yorkshire and of the "Splint" coal from Whitehill Colliery, 

 near Edinburgh. He mentioned that Prof. Huxley had drawn 

 attention to the former as containing in quantity sporangia and 

 spores of plants allied to the recent club mosses. Mr. Wethered 

 averred that these were only found in numbers in the topmost 

 three inches of the coal-bed, but very sparsely in the lower por- 

 tion of the seam. In the Edinburgh splint coal only four inches 

 of the basal and but a part of the upper layer contained spores. 

 Macrospores and microspores were present in both the coals, 

 and, judging from these, he regarded them as belonging to 

 plants resembling or allied to the recent genera Stlaginrila or 

 Isoeles. Mr. W. Carruthers replied, and dissented from this 

 view. — Dr. F. Day read a paper on the rearing, growth, and 

 breeding of salmon in fresh water in Great Britain. He referred 

 to the statements and opinions of the older authorities, and then 

 dwelt more at length on the more recent experiments of Si 

 Tames Maitland at Howietoun. In December, 1SS0, Sir lame 



