April 22, 1880] 



NATURE 



587 



appending any criticism on the admissibility or otherwise of 

 this analogical piece of reasoning, we will simply narrate 

 the results of putting the question to the test of experi- 

 ment. When oxalate of lime was deposited in a gelatin 

 plug between the poles of horseshoe magnets, " there was 

 an extraordinary increase in the size of all the forms, 

 crystalline and non-crystalline, where the plug or gelatin 

 was subjected to the action of magnetism, but there was 

 no production of new forms or greater tendency to 

 sphericity." Similar experiments with a large electro- 

 magnet yielded crystals which in several cases appeared 

 to have their axes slightly twisted. This observation, if 

 confirmed, and if presenting any assignable relation 

 between the direction of magnetisation and that of the 

 alleged axial twist, would be in the highest degree inter- 

 esting. Up to the present moment, so far as we are 

 aware, no crystal presenting tetratohedral dissymmetry 

 or optically active in the polarimeter has been procured 

 by artificial synthesis. Is it possible that Dr. Ord's 

 observation contains the germ of the method by which 

 we may hope to procure the synthesis, not of the active 

 tartrates and sugars only, but of quinine and other alka- 

 loids also ? Experiments with electric currents were also 

 tried, but proved less satisfactory, though the electrolytic 

 actions set up produced several unexpected results. 



Later chapters in Dr. Ord's book are devoted to renal 

 and biliary calculi other than those mentioned— including 

 a very singular case of an indigo calculus — and to a short 

 scheme for the qualitative examination of calculi, which 

 contains valuable hints to the general practitioner. 



Concerning the production of the collosphcres them- 

 selves there does not appear to be any one assignable 

 cause. Harting dwells strongly on the influence of the 

 "nascent" state in which the crystalloid body is deposited 

 by double decomposition within the colloid. This term 

 will probably fall out of use by chemists so soon as they 

 perceive that it is a term convenient only as a cloak for 

 ignorance. A more satisfactory point is made by Dr. 

 Ord in the suggestion that there exists a relation yet 

 undiscovered between hydration and the colloidal state ; 

 the hydrate of fresh uric acid being a colloid. Dr. Ord is 

 of opinion that hydrated colloids and strong solutions of 

 very soluble salts alike prolong the colloidal state of 

 certain crystals, thus favouring the production of spheroids 

 Dehydration, which in certain cases appears to determine 

 the production of spheroidal forms, is obviously inad- 

 missible as the cause in the majority of cases. Nor does 

 the difference of crystalline form between one crystal- 

 system and another appear to affect the collospheric 

 condition, in which absolutely no smallest modifications 

 attributable to this possible cause can be detected. 

 Solubility undoubtedly has much to do with the matter, 

 since insoluble crystalline substances yield the best 

 spheroids ; but by evaporation and by deposition from 

 hot strong solutions even sulphate of copper and ferro- 

 cyanide of potassium can be thus obtained. We must 

 therefore fall back upon the conclusion that the one 

 important factor in the production of the collospheric 

 condition is the influence of the colloid. Mr. Rainey 

 who came to this conclusion, attributed this action to the 

 "viscosity'' or tenacity of. the colloid fluid ; and hence he 

 associates with true colloids such substances as glycerine 

 (which is a true crystalloid) and other viscid substances. 



Dr. Ord, on the other hand, is disposed to regard the 

 influence of the colloid as "a result of intestinal mole- 

 cular movement inherent to the constitution of the 

 colloid." 



Arrived at this point, however, we cease to perceive 

 any definite coherence between the various specula- 

 tions which follow and in which the effects of pres- 

 sure, of strain, and of hypothetic spiral waves, are 

 mixed up with Brownian movements and chemical inter- 

 action. It is a pity that the all-important bearing of 

 surface-tension at the boundary of two media, and of the 

 elegant and instructive researches of Plateau, including 

 his production of liquid spheroids, is not once alluded to, 

 even in the remotest manner, by Dr. Ord. For our own 

 part, we are disposed to attribute a very large portion of 

 the influence which determines the production of these 

 collospheres of solid matter to] the same molecular 

 actions as those which produce the surface-tensions 

 between solids and liquids, and which cause the rise of 

 liquids in capillary tubes and the production of liquid 

 spherules in the experiments of Plateau. 



In conclusion we must not omit to quote one experi- 

 ment of Dr. Ord, that in which the rapid production of 

 the collospheres is conducted under conditions suitable 

 for lecture demonstration. A solution of pure urea of 

 density I 026 usually throws down shining white flakes of 

 nitrate of urea on the addition of an equal bulk of strong 

 nitric acid. If, however, a little egg-albumin be added to 

 the urea solution before the nitric acid is added, spheres 

 are formed of the greatest beauty, and appear " floating 

 like snowballs " in the yellowish liquid. 



OUR BOOK SHELF 

 A Guide for the Electric Testing of Telegraph Cables. 



By Capt. V. Hoskixr. Second Edition. (London : 



E. and F. N. Spon, 1879.) 

 THIS very unpretentious but very useful little manual 

 has reached a second edition, and now reappears with 

 several valuable additions. In his original preface the 

 author states that he does not expect an electrician to 

 discover anything new in its pages. Be that as it may, 

 the electrician will acknowledge the debt he owes to 

 Capt. Hoskiarr for the precision and brevity with which 

 all his directions concerning the practical details of testing 

 are given. Without philosophising or going into mathe- 

 matical reasons of why and wherefore, he gives the 

 necessary formula: in the shape most useful for practical 

 calculations ; and the necessary tables of logarithms, 

 trigonometrical functions, and temperature coefficients are 

 sufficiently complete to save reference to other more 

 extended works. The twelve lithographed diagrams leave 

 nothing to be desired in point of clearness. 



LETTERS TO THE EDITOR 



[ The Editor docs not hold himself responsible for opinions expressed 

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 munications containing interesting and novel facts.] 



The Antiquity of Oceanic Basins 

 It seems to have escaped Dr. Carpenter's notice * that, in a 

 Report en the results of the Deep-sea Dredgings of Mr. Pourtales 

 1 Lecture before the Royal Institution, January, 1880. 



