April 1 8, 18S9] 



NA TURE 



597 



August 1886, on the occasion of the Eclipse Expedition of 

 that year to Grenada. 



The instruments employed were magnetometer Elliott No, 

 61, and Dip Circle Dover 83, belonging to the Science and Art 

 Department. 



The method of observation was similar to that adopted in the 

 Magnetic Survey of the British Isles for epoch January i, 1886, 

 lor which these instruments were also employed. 



The results may be thus summarized : — 



boiling-point of mercury for most, 

 follows : — 



The results obtained are as 



Station : August i8£6 Inclination 



Declina- 

 tioQ 



Horizontal Total 



I 



St. George, Grenada 

 Hog Island, Grenada 

 Island of Carriacou 



40 547 I 3 1093 



41 14-1 i 3-1000 

 — ! 3'077i 



4"ii44 4i'5 E. 



4-1223 osrsE, 



— ioi6-^E. 



Linnean Society, April 4,— Mr. Carruthers, F.R.S., Pre- 

 sident, in the chair. — Mr. D. Morris exhibited a specimen of the 

 hymenopterous insect, Eulema cayennensis, concerned in the fer- 

 tilization of Cdryanthcs viacrantha (see Criiger, Journ. Linn. 

 Soc, viii. 129), and obtained from Mr. Hart of Trinidad. Re- 

 ferring to the illustrations of the structure of the flowers, given 

 in the Gardetier's Chronicle (xvii., 1882, 593 ; and xxiii., 1885, 

 145), Mr. Morris explained the process carried out by the in- 

 sects, chiefly bees, in removing the poUinia and subsequently at- 

 taching them on the stigma. The observations of Criiger had 

 been verified by Mr. Hart in the Botanic Gardens, Trinidad. — 

 Sir Edward Fry exhibited and made some instructive remarks on 

 a copy of Grisley's "Viridarium Lusitanicum," 1661, presented 

 by Linnceus to his pupil Loefling, the author of the " Iter 

 Hispanicum." — Prof. R. J. Anderson exhibited some photo- 

 graphs of educational museum cases in Queen's College, 

 Gal way.— A paper was read by Mr. Lister on the Myxomycekes, 

 or Mycetozoa, a group of organisms on the borderland between 

 the animal and vegetable kingdoms, and formerly classed with 

 Fungi. His remarks were illustrated by numerous coloured 

 drawings of representative species, and the author also exhili:ed j 

 under the microscope the swarm cells from the spores of I 

 Aniaurohicte and tlie streaming plasmodium of Badhamia. 

 Attention was especially directed to the mode of feeding of the 

 swarm cells and observations made on those of Steinonitis, 

 where large bacilli were seen to be caught by pseudopodia pro- 

 jected from the posterior end of the organism, and drawn into 

 its substance and digested. An interesting discussion followed, 

 in which the President, Prof. Marshall Ward, Prof. Howes, an 1 

 Mr. Breese took part. — A paper was then read by Mr. E. W. 

 Hoyle, on the deep-water fauna of the Firth of Clyde, em- 

 bodying the results of recent investigations. The explored area, 

 which is shut oft' from the Irish Sea by a submarine plateau ex- 

 tending from the Mull ofCantyre to the Ayrshire coast, contains 

 seven distinct deep-water basins, in which the depth exceeds 

 20 fathoms, and in some cases reaches 80 or lOJ fathoms. An 

 account was given of the dredging which had been carried on, 

 with lists of the species obtained at v.irious depths. A discussion 

 followed in which Messrs. John Murray, W. P. Sladen, a:id 

 G. B. Howes took part. 



Chemical Society, March 21.— Mr. W. Crookes, F.R.S., 

 in the chair.— The following papers were read :— The molecular 

 weights of metals (preliminary notice), by Prof W. Ramsay, 

 F. R.S. The molecular weights of a number of metals have 

 been determined by Raoult's vapour-pressure method, viz. by 

 ascertaining the depression of the vapour- pressure of the solvent 

 produced by a known weight of dissolved substance, the relation 

 between molecular weight and depression being expressed by 



W X P X /> 

 the equation, W = /, where W is the molecular weight 



' 100 X(/ ' =• 



to be found; W the molecular weight of the solvent; P/ioo 

 the percentage weight of the dissolved substance in solution ; 

 / the vapour-pressure of the solution ; and d the depression in 

 the vapour-pressure of the solvent produced by adding the sub- 

 stance dissolved. The solvent employed was liquid mercury ; 

 the temperatures 260° and 270° for a few substances, and the 



These numbers represent some of the actual results. Never- 

 theless, they must not be taken as absolute ; although in many 

 cases they are conclusive as to the molecular weight of the 

 metal, still further experiments are needed. As an instance 

 ( f what occurs, the metals thallium and antimony may be 

 cho>en. With thallium, for example, the following results were 

 obtained : — 



Percentage of thallium . Molecula r weigh t. 



in amalgam. . p^^^^ Calculated.' 



0-8191 157-4 204-2 



1-666 183-5 204-2 



2894 1743 204-2 



3290 183-9 2042 



No appreciable change is produced on concentration. But with 

 antimony, the molecular weight increases proportionately to the 

 amount present, thus — 



Here an association of atoms is evidently in progress. The 

 results are based on the assumption that the molecular formula 

 of mercury is Hg^, in favour of which strong reasons can be 

 adduced. — The application of Raoult's depression of melting- 

 point method to alloys, by Messrs. C. T. Heycock and E. H. 

 Neville. As a result of some preliminary experiments on the 

 change in the solidifying point of tin caused by the addition of 

 small quantities of other metals, the authors conclude that the 

 dissolution of a metal in tin follows the same laws as that 

 of compounds in other solvents, i.e. (i) that the fall in tem- 

 perature of the solidifying point is directly proportional to the 

 weight of metal added ; and (2) that the fall of temperature is 

 inversely as the atomic (molecular ?) weight of the metal added. 

 With tin, copper, silver, cadmium, lead, and mercury, the dis- 

 solution of one atomic proportion in 10 J atomic proportions of 

 tin caused a fall in temperature of the solidifying point varying 

 from 2''-i6 to 2°-67, with aluminium a fall of i°-34, and with 

 antimony a rise of 2°-o. In the discussion which followed the 

 r.-ading of these paper.^ Prof. Arm.-trong said that notwithstand- 

 mg the apparent regularity and simplicity of the result?, he was 

 not prepared to accept them as in the least degree Snal, There 

 was not sufficient evidence in his opinion that the effect observed 

 was not in part at least the outcome of a change in the molecular 

 composition of the solvent. The results obtained by Raoult'.s 

 methods were, he thought, comparable with those obtained by 

 determining the specific heats of the elements ; in the latter case 

 the observations were undoubtedly made with masses of mole- 

 cule.«, which probably were of varying degrees of atomic 

 complexity, and yet the results were found to be such as to 

 justify conclusions being drawn as to the relative magnitudes of 



