November 1, 1901.] 



SCIENCE. 



697 



addition of cesium chlorid to a solution contain- 

 ing both the trichlorid and the pentachlorid of 

 antimony, and was considered to be a mixed 

 salt. In recovering cesium from some residues 

 containing antimony, the authors precipitated 

 it as the chloroplumbate. Instead of being 

 yellow, like the pure salt, the lead salt was 

 bright green, and examination showed that it 

 was colored by an antimony salt, which was 

 isomorphous with it. This proved to be Setter- 

 berg's salt, and showed from its isomorphism 

 that its constitution is Cs^SbCle, containing 

 therefore quadrivalent antimony. It crystal- 

 lizes in black octahedra and belongs to the 

 series of salts of which the most familiar mem- 

 ber is the potassium chloroplatinate. This is 

 the first known salt in which antimony is quad- 

 rivalent, although in the dioxid this valence is 

 accepted by many chemists. 



An interesting application of the bioscope in 

 crystallography is described in a paper recently 

 presented to the American Academy of Arts 

 and Sciences, by Professor Richards, of Harvard 

 University, in conjunction with E. H. Archi- 

 bald. The authors have studied the growth of 

 crystals by photomicrography, taking succes- 

 sive instantaneous photographs of the growing 

 crystal. This was accomplished with a very 

 considerable degree of success, after overcom- 

 ing very great mechanical difficulties. The 

 object was especially to study the birth of crys- 

 tals in order to determine whether crystalliza- 

 tion is always preceded by the separation of an 

 initially liquid phase, consisting of a supersat- 

 urated solution of the former solvent in its 

 foi'mer solute. A number of observers have 

 believed that with high microscopic powers 

 they have detected the formation of minute 

 globules at the moment of precipitation, and 

 that these globules have soon joined and as- 

 sumed crystalline form. The problem seemed 

 possible of solution by taking a series of photo- 

 graphs of a solution just at the point of crystal- 

 lization, and a large number of such photo- 

 graphs were obtained. The enlargement was 

 over 4,000 diameters and both common and 

 polarized light were used. In every case the 

 earliest appearance of the crystal was distinctly 

 crystalline, and no signs of globules were found. 

 Hence if these occur preceding the crystal 



phase, they are too small to be detected in a 

 microscope of the power used. Incidentally it 

 was found that the growth in diameter in 

 the first second of the crystal's existence was 

 vastly more rapid than during the subsequent 

 period. "This exceedingly rapid initial dia- 

 metric growth accounts for a lack of definition 

 noticed in the first images — a lack of definition 

 sufficient to have misled the eye, but not 

 enough wholly to obscure the photographic 

 evidence of crystalline structure." The same 

 apparatus is now being used for the study of 

 the change in the structure of steel at high 

 temperatures. 



That the question of the influence of boric 

 acid and borax upon the health has not yet 

 been definitely settled is evidenced by two 

 papers on the subject, which have recently 

 appeared in the Journal of Hygiene and the 

 British Medical Journal. The first of these, by 

 Tunnicliffe and Rosenheim recounts a series 

 of experiments upon children, continued for 

 twelve days, and the authors draw the conclu- 

 sion that these substances are practically harm- 

 less. The other paper by Gruenbaum combats 

 the deductions of the former, chiefly upon the 

 grounds that the experiments were too few, 

 continued for too short a period and were upon 

 children over the age when milk is the princi- 

 pal article of food. In the author's opinion 

 the fact that the boric acid and borax were 

 rapidly excreted by the kidneys is evidence of 

 their poisonous character. 



In a recent number of the Comptes Rendus 

 Chaveau and Tissot answer the question as to 

 whether an atmosphere which has been ren- 

 dered deleterious by the presence of hydrogen 

 sulfid can act as a poison through the skin or 

 the outer mucous membrane, in the negative. 

 A dog, with a canula connected with the out- 

 side air in its trachea, was placed in a closed 

 box containing more than eight per cent, of 

 hydrogen sulfid. After an hour the dog was 

 still in good condition, while another dog not 

 thus protected, succumbed in the poisonous 

 atmosphere almost instantly. The authors con- 

 clude from this experiment that hydrogen sul- 

 fid acts as a poison only when taken into the 

 lungs. J. L. H. 



