270 



SCIENCE. 



[N. S. Vol. XIX. No. 476. 



chine had siiificient power to fly, sufficient 

 strength to withstand the shock of landing, 

 sufficient capacity to control. Winter had 

 already set in when the last trials were made, 

 but these facts were definitely established, and 

 we know that the age of the flying machine 

 has come at last. — Wilbur Wright in The In- 

 dependent. . 



NOTES ON INORGANIC CHEMISTRY. 



Two papers have recently appeared in this 

 country which, while not directly concerned 

 with inorganic chemistry, have an important 

 bearing on it. The first of , these is a ' New 

 Method for Determining Compressibility,' by 

 Theodore William Richards and Wilfred New- 

 some Stull, and is published by the Carnegie 

 Institution. Very little work has been pre- 

 viously done on the compressibility of inor- 

 ganic substances, although such investigations 

 are calculated to throw light upon the subjects 

 of chemical afiinity and cohesion. New meth- 

 ods have been devised by which the compressi- 

 bility of nearly all solids and liquids can be 

 determined up to 600 atmospheres or more. 

 By means of these methods Richards and Stull 

 have determined the compressibility at 20° of 

 iodin, bromin, carbon tetrachlorid, chloro- 

 form, bromoform, water, phosphorus and mer- 

 cury, while that of ehlorin was estimated by 

 extrapolation. Bromin is much more com- 

 pressible than iodin, and it is probable that 

 ehlorin is still more compressible, being rather 

 more than twice as compressible as water. 

 Phosphorus is hardly half as compressible as 

 water, while mercury was the least com- 

 pressible substance measured, having a value 

 less than ten per cent, that of water. In 

 every case the compressibility decreases with 

 increasing pressure. The authors suggest the 

 use of the term megabar to indicate the pres- 

 sure of a megadyne on a square centimeter, 

 giving an absolute standard instead of the un- 

 scientific unit of an atmosphere. The value 

 of a megabar is 75.015 centimeters of mercury 

 or 98.703 per cent, of an ' atmosphere.' This 

 the authors point out is more nearly the av- 

 erage pressure at the laboratories of the world 

 than the arbitrary ' atmosphere ' usually taken. 



The second paper is on ' The Electrical Con- 



ductivity of Aqueous Solutions at High Tem- 

 peratures,' by Arthur A. Noyes and William 

 D. Coolidge. This is the first contribution 

 from the recently established research labora- 

 tory of physical chemistry of the Massaclui- 

 setts Institute of Technology, and concerns 

 the description of the apparatus used and the 

 results with sodium and potassium chlorid up 

 to 306°. Great difficulty was encountered in 

 devising a suitable conductivity cell which 

 should fulfil the other necessary conditions 

 and be capable of withstanding the great pres- 

 sures at high temperatures. The cell finally 

 found satisfactory was a platinum-lined soft 

 crucible steel cell, with gold wire packing and 

 quartz insulation. In the experiments with 

 sodium and potassium chlorids it was found 

 that the degree of dissociation decreases with 

 the temperature. With tenth-normal solution 

 of sodium chlorid this decrease is very rapid, 

 from about 83 per cent, at 18°, to 60 per cent, 

 at 306°, and indicates that the degree of dis- 

 sociation is very small at the neighborhood of 

 the critical temperature (about 360°). The 

 conductivity of the vapor over a tenth-normal 

 solution of potassium chlorid at 306° was too 

 small to be observed with the apparatus, and 

 is at all events exceedingly small. The in- 

 vestigations with this cell are being continued 

 and it is hoped to extend the observations up 

 to the critical temperature. 



To the ' Qiiarterly Statement of the Pales- 

 tine Exploration Fund ' a paper is contributed 

 by William Ackroyd on a principal cause of 

 the saltness of the Dead Sea. After showing 

 the insufficiency of the soil and rocks to fur- 

 nish more than a fraction of the salt present, 

 and that the theory that its saltness is due to 

 its being a former arm of the Red Sea, which 

 has gradually become concentrated, is not 

 substantiated by facts, he claims that the most 

 important cause is the atmospheric transporta- 

 tion of salt from the Mediterranean. As in 

 ojther localities, the rain water would be 

 charged with salt to a degree which varies in 

 a direct manner with the velocity of the winds 

 coming from the sea. This view is confirmed 

 by the fact that the ratio of ehlorin to bromin 

 is approximately the same as that for these 

 two elements in the Mediterranean. 



