November 26, 1891] 



NA TURE 



93 



excess of sulphuric acid at a low temperature, three isomerides 

 are formed— namely, /ara-nitro-ortho-toluidine (about 75 per 

 cent.), w^/a-nitroortho-toluidine, C6H3Me(NH„)(N02)[i : 2 : 5] 

 (about 3 or 4 per cent.), and ^A//i(J-nitro-ortho-toluidine, 

 C,iH3Me(NH2)(i\0.,)[t : 2 : 6] (about 20 per cent,). The separa- 

 tion of the ortho-nitro-ortho-toluidine from the mixture is 

 effected by taking advantage of the greater solubility of this 

 isomeride in slightly warm water. The authors give a table of 

 the properties of the ortho- and para-nitro-ortho-toluidines, and 

 of their products on reduction and other derivatives.— Researches 

 on the gums of the arabin group ; Part ii. Geddic acids — 

 Gedda gums ; the dextro-rotatory varieties, by C. O'Sullivan. 

 The Gedda gums described consist of the calcium, magnesium, 

 and potassium salts of gum acids, the calcium salt pre- 

 dominating, and more or less nitrogenous matter, which is 

 probably combined with a true gum acid. They dissolve easily 

 in water, forming a yellow or reddish syrup, neutral to test- 

 paper, which is dextro-rotatory. The gum acids are obtained 

 pure by dialyzing their acidified solution, and by fractional 

 precipitation with alcohol. The gum acids in any one sample 

 of gum bear a very simple relation to one another, and are 

 closely related to the gum acids contained in other samples. A 

 table of their relationships is given. The composition and 

 partial constitution of any one of the gum acids which have been 

 as yet examined may be expressed by the general formula, 

 C23H38-2„02.2-„.nC,2H2oOjo.pCioH]60g. Thcsc gum acids, 

 when heated at Sb^-ioo" for 10-30 minutes with a solution con- 

 taining 2 percent. 11,804, are hydrolyzed, yielding arabinon and 

 a gum acid of lower molecular weight. The gum acids thus pro- 

 duced closely resemble the gum acids existing in the natural 

 gums, but are less optically active and more insoluble in weak 

 alcohol. The most marked difference between these gum acids 

 and those existing in the natural gums is that they are only 

 hydrolyzed with difliculty with 2 per cent, sulphuric acid. They 

 are, however, slowly broken down by several hours' digestion, 

 and acids of successively lower weight are formed. The lowest 

 stage of the hydrolysis is represented by the general equation : — 



C23H38-2n022-n-nCi,H.2oO,o + 3nH.O 



= C03H38O22 + 2nC6Hi20fi. 

 The compound CosHjgOss has not yet been obtained in sufficient 

 quantity for an examination of its properties. Those gum acids 

 obtained from Gedda gum are highly dextro-rotatory, whilst 

 those from gum arable, although otherwise identical, are in- 

 active. — Some compounds of the oxides of silver and lead, by 

 Emily Aston. The author finds that on following the direc- 

 tions given by Wohler for the preparation of the compound 

 AgoO,2PbO the product varies in composition. A substance of 

 the composition 2Ag20,PbO is obtained when a mixture of lead 

 and silver hydroxides is allowed to stand in presence of caustic 

 soda, and also by precipitating the mixed nitrates of lead and 

 silver, and exhaustively extracting with caustic soda. — The 

 electrolysis of potassium acetate solutions, by Dr. T. S. Murray. 

 On electrolyzing a dilute aqueous solution of potassium acetate 

 only hydrogen and oxygen are evolved ; with concentrated solu- 

 tions a mixture of ethane, hydrogen, oxygen, methyl acetate, and 

 carbon dioxide is evolved. On diluting the solution the amount 

 of ethane decreases, at first very slowly, but finally with great 

 rapidity. Reducing the current has a similar influence. With 

 rise in temperature, the ethane diminishes, and ceases to be 

 formed at ico^ In contradiction to Jahn, the author finds that the 

 employment of a large anode reduces the yield of ethane ; the 

 largest yield is obtained with a very small anode ; variations in 

 the cathode do not influence the electrolysis. The results of the 

 experiments are illustrated by curves. The author believes that 

 the ethane is formed, not by partial oxidation of acetic acid, but 

 by a simple interaction of the acetions (CH3COO). He finds 

 that the yields of ethane from equivalent solutions of potassium, 

 sodium, and calcium acetates are equal. — A new method of 

 preparing 3-dinaphthylene oxide, and the constitution of its 

 tetra-sulphonic acid, by W. R. Hodgkinson and L. Limpach, 

 Beta-dinaphthalene oxide is obtained by heating 2 : 3' /3-naphthol- 

 sulphonic acid to low redness ; the distillate is freed from 6- 

 naphthol by extraction with alkali, and the residue crystallized 

 from acetic acid. It crystallizes in rhombic plates, and melts at 

 153'. On sulphonation it yields a tetra-sulphonic acid, which 

 is identical with the product obtained by the continued action of 

 sulphuric acid on 3-naphthol. 



Linnean Society, November 5.— Prof. Stewart, President, 

 in the chair.— On behalf of a number of subscribers, Mr. 



NO. 



II52. VOL. 45] 



Carruthers presented to the Society a half-length portrait in oils 

 of Sir John Lubbock, Bart., M.P., P.C., F.R.S,, a former 

 President, painted by Mr. Leslie Ward ; and the remarks 

 which he made on the services rendered to biological science by 

 Sir John Lubbock drew from the latter a graceful acknowledg- 

 ment of the honour conferred upon him. — Amongst the exhibi- 

 tions which followed, Mr. E. M. Holmes showed some new 

 marine Algae from the Ayrshire coast ; Mr. J. G. Grenfell 

 showed some Diatoms with pseudopodia, illustrating his remarks 

 with diagrams, upon which an interesting discussion followed. — 

 The President exhibited and made some observations on a tooth 

 of the walrus, which illustrated in a curious manner the periods 

 of growth.— Mr. R. V. Sherring called attention to a large 

 series of framed photographs which had been taken under his 

 direction in Grenada, and illustrated the general character of 

 the West Indian flora as well as the physical features of that 

 particular island. — Mr. J. E. Harting exhibited a specimen of 

 Wilson's Petrel which had been picked up in an exhausted 

 state in the Co. Down on October 2 last, and had been for- 

 warded for inspection by Mr. R. Patterson, of Belfast. Mr. 

 Harting gave some account of the species, and remarked upon 

 the unusual number of Petrels, Shearwaters, Skuas, and other 

 marine birds which had been driven inland to a considerable 

 distance during the recent gales. — A paper was then read by 

 the .Rev. Prof. Henslow, entitled "A Theory of Heredity 

 based on Forces instead of any special form of Matter." The 

 author maintained that no special form of matter (as is generally 

 supposed) other than protoplasm is required ; the latest dis- 

 coveries of the organized structure of protoplasm militating 

 against the idea of any other special form of matter. Taking 

 illustrations from the animal and vegetable kingdoms, he 

 inquired why two varieties of chickens fed from the first day to 

 full growth were different ? It seemed to him more probable that 

 the results were due to different arrangements of the same kinds 

 of molecules rather than to different kinds of "germ-plasm." 

 Raiuiticuhts heterophyllis, he pointed out, produced a "land- 

 form" and a " water-form " according to its environment ; it 

 therefore exhibited both " heredity " and " acquired characters." 

 As the materials of its structure were the same in both cases, 

 the different results, he considered, must be due to different 

 arrangements of its molecules, and must be effected by forces. 

 The sudden appearance of stomata on the "land-form" illus- 

 trated a case of forces normally "potential " while the leaf is 

 submerged, becoming "actual" when the leaf developed in air. 

 After some further deductions. Prof. Henslow concluded that 

 protoplasm and the forces bound up with it were perfectly able 

 to do all the work of transmitting parental characters, as well 

 as to acquire new characters, which in turn might become 

 hereditary as well. 



Physical Society, November 6.— Dr. E. Atkinson, Vice- 

 President, in the chair. — Prof. Sydney Young read a paper on the 

 generalizations of Van der Waals regarding " corresponding " 

 temperatures, pressures, and volumes, in which he gave the 

 results of an investigation made with a view of testing whether 

 these theoretical deductions agree with experimental facts. 

 From his virial equation, 



(^^;)<= 



h) =R(i -}- a/), 



Van der Waals showed that, if the absolute temperatures of 

 various substances be proportional to their absolute critical 

 temperatures, their vapour pressures will be proportional to 

 their critical pressures, and their volumes, both as liquid and 

 as saturated vapour, will be proportional to their critical volumes. 

 These deductions have now been put to the test of experiment. 

 Some years ago, Prof. Ramsay and the author published data 

 relating to the temperatures, pressures, and specific volumes of 

 methyl-, ethyl-, and propyl-alcohols, ether, and acetic acid. 

 Since then, experiments have been made on benzene and its 

 halogen derivatives — fluor-, chloro-, bromo-, and iodo-benzene — 

 carbon tetrachloride and stannic chloride, and in a few cases 

 the observations have been carried to the critical points. The 

 critical volumes being in many cases difficult to determine 

 with any exactness, the author, instead of expressing the tem- 

 peratures, pressures, and volumes of each substance in terms 

 of their critical values, found it necessary to compare the various 

 substances with one of them taken as a standard. Fluorbenzene 

 was chosen as standard on account of the very simple relations 

 observed between the monohalogen derivatives of benzene, and 

 the fact of its criticil constants (temperature, pressure, and 



