March 25, 1880] 



NATURE 



499 



the rarest or most out-of-the-way animals can be fished 

 up at five minutes' notice, and the time of appearance of 

 this or that form, of the eggs of another, of the larvae of 

 another, is so precisely ascertained that the zoologist can 

 go — not in his present hap-hazard fashion, to study any- 

 thing which may turn up — but definitely primed and 

 prepared to settle an important question in relation to a 

 form which he is sure to obtain. 



These advantages, and the honour of being the first 

 University to possess a sea-side laboratory of its own, 

 cannot be secured by the Johns Hopkins University with- 

 out a certain definite outlay of money. What may be the 

 cost of buildings and of permanently employing a fisher- 

 man, two attendants, and a scientific director in the 

 United States, it is difficult to guess, but nothing less 

 than an expenditure of 5,000/. on the building and an 

 annual outlay of 700/. would give such an experiment a 

 fair chance of success in this country. 



E. Ray Lankester 



THE SOLUBILITY OF GASES IN SOLIDS 

 TV/TESSRS. HANNAY and Hogarth recently communi- 

 ■*•*•'■ cated to the Royal Society an important paper on 

 the Solubility of Solids in Gases. The subject, an outline 

 of which was given to our readers in an abstract of a 

 preliminary paper by the same authors a few weeks ago, 

 has attracted the more notice since it led Mr. Hannay to 

 the research upon the artificial production of crystallised 

 carbon, which is associated with his name. 



The original purpose of Messrs. Hannay and Hogarth 

 in undertaking this research was to investigate the condi- 

 tion of gases at their "critical point" with respect to their 

 solvent power. For if at the critical point there really 

 occurs a transition from liquid to gaseous state, and if the 

 property of solids is one possessed by liquids alone, there 

 ought to be precipitation of the dissolved solid matter as 

 the substance passes through the critical point. If no 

 su:h precipitation occurred, this would furnish an inde- 

 pendent proof of the perfect continuity of the liquid and 

 gaseous states, in addition to the proofs derived from the 

 observed relations of temperature and pressure, and from 

 the inability of optical tests to discriminate between gas 

 and liquid in the condition of matter raised above its 

 critical temperature. 



A simple qualitative experiment was therefore under- 

 taken as a preliminary test of the matter. "A solution 

 of potassic iodide in alcohol was prepared, and a strong 

 tube filled to about one-half with the solution. After 

 sealing the tube was placed in an air-bath, and heat 

 applied. No precipitation of solid could be seen even at 

 a temperature of 350° C, more than ioo° C. above the 

 critical point of alcohol." A solution of resin in paraffin 

 spirit showed no trace of decomposition at 360 C. under 

 similar conditions. 



To permit of experimenting under more exact condi- 

 tions, a modification of Andrews's apparatus was devised, 

 which, from its simplicity and efficiency deserves mention. 

 A T- tube of wrought-iron of ^-inch internal and i-inch 

 external diameter was furnished with wrought-iron screw 

 caps. Through one of these the pressure-screw works ; 

 through the opposite end the experimental tube is fixed.' 

 The side-branch, about 3 inches long, admitted an air- 

 manometer. The apparatus, which was less than 12 

 inches in length, was filled wiih mercury. The device 

 for packing consisted in the employment of stout indii- 

 rubber plugs. Where the pressure-screw passed through 

 the rubber the latter was protected by a greased leather 

 lining. When high pressures were employed the tube 

 was cemented in with oxychloride of zinc. This extremely 

 simple method of packing was so perfect as to give 

 freedom of motion without leakage even at the enormous 

 pressure of 880 atmospheres. 



With this apparatus it was demonstrated that a clean 



crystal of potassic iodide dissolved gradually away in 

 pure alcohol gas (the term gas referring, as Andrews 

 suggested, to the fluid, at any temperature above its 

 critical point). Bromide of potassium, and chloride 

 of calcium were also found to be soluble in alcohol gas. 

 Cobaltous chloride remained in solution at 320 C, and 

 continued to exhibit its characteristic blue colour. It 

 even showed a spectrum identical with that shown at 

 15° C. The spectrum of the acid decomposition product 

 of chlorophyll similarly dissolved in alcohol, gives identical 

 spectra at 350° C, and 15° C, though in air it decom- 

 poses below 200° C. 



Other experiments with sulphur, selenium, and arsenic 

 in bisulphide of carbon gave interesting but less con- 

 clusive results. The question whether the critical point 

 of a gas is altered by having a solid dissolved in it 

 appears to be affirmatively decided ; for the authors 

 found that while the critical point of pure alcohol is 

 234 0, 6 C. at a pressure of that of 65 atmospheres, alcohol 

 containing potassic iodide was 237 at a pressure of 7fi 

 atmospheres. 



Further attempts were made to obtain solutions of 

 sodium in ammonia, gas, and hydrogen, in the latter case 

 with partial success. 



As a final conclusion the authors claim that 'these 



experiments, made at temperatures much further removed 



I from the critical point than those from which Andrews 



I reasoned, afford further proof of the perfect continuity of 



J the liquid and gaseous states, and also complete proof of 



the solubility of solids in gases. 



THE LATE MR. THOMAS BELL, F.R.S. 



TO few men does English biological science owe more 

 than to the veteran zoologist whose death we briefly 

 recorded in Nature, vol. xxi. p. 473. Born at Poole, in 

 Dorsetshire, on October 11, 1792, Thomas Bell was edu- 

 cated as a surgeon-dentist, and on his establishment in 

 practice in London he soon gained a high professional 

 reputation. From an early period of life he devoted his 

 leisure hours to zoological studies, and the fruits of his 

 careful and conscientious labours are preserved in his 

 numerous contributions to the Transactions and P>oceed- 

 ings of the Linnean, Geological, and Zoological Societies, 

 and in his well-known manuals on " British Quadrupeds," 

 "Reptiles,'' and "Stalk-eyed Crustacea." These latter 

 formed part of the series of works published by Mr. Van 

 Voorst, which have done so much to spread a knowledge 

 of the natural history of our islands ; and Mr. Bell was 

 specially adapted to such a task, having a happy faculty 

 of conveying scientific information in such a form as to 

 be attractive to the general reader. A still more impor- 

 tant undertaking was his illustrated folio, " Monograph 

 of the Testudinata," begun in 1S36, but unfortunately 

 the publisher failed when only eight parts had appeared ; 

 the plates, along with some which had remained unpub- 

 lished, were re-issued to the public in 1S72 by Mr. 

 Sothern, with letterpress by the late Dr. J. E. Gray. 



But the services which Mr. Bell rendered to science 

 were far from being confined to his published writings. 

 From 1848 to 1853 he was one of the secretaries of the 

 Royal Society, of which he had been elected a Fellow in 

 i8:S, and his business habits, energy, and personal 

 popularity enabled him greatly to advance its interests. 

 On his resigning this secretaryship in 1S53 he was elected 

 President of the Linnean Society, of which body he had 

 been a member since 1S15. N cither the scientific standing 

 nor the financial position of the Society were then in a 

 state at all worthy of its name and traditions, and the 

 new President set vigorously to work at its reform. By 

 personal example and influence in procuring suitable 

 papers and in assuring good attendances, by an active 

 enlistment of new members, and a rigorous supervision 

 of expenditure, and by generous private donations to the 



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