2 OS ANNUAL RECORD OF SCIENCE AND INDUSTRY. 



cipitated. J. L. Davies has found it to be possible to precip- 

 itate nickel in a similar manner, it being necessary, however, 

 to render the nickel solution strongly ammoniacal. The zinc 

 is used in the form of filings, and the nickel is thrown down 

 distinctly metallic and in a weighable condition. The ex- 

 periments were made with solutions of the sulphate and the 

 chloride of nickel. 21 A, April, 311. 



ABSORPTION OF HYDROGEN BY METALS. 



Not lomr as;o Troost and Hautefeuille announced that so- 

 dium, potassium, and palladium absorbed hydrogen to form 

 alloys of definite composition. They now present the results 

 of similar investigations with iron, cobalt, and nickel. These 

 metals absorb hydrogen largely, but to different degrees un- 

 der different circumstances, not forming genuine compounds. 

 Thus an in<xot of nickel under favorable conditions will ab- 

 sorb one fifth its volume of the gas. The same metal in an 

 electrolytic film can be made to take up forty volumes, 

 while pulverulent nickel can dissolve nearly one hundred 

 times its bulk of hydrogen. With each of the three above- 

 named metals the pulverulent or pyrophoric modification has 

 the highest absorptive power, and the compact form the low- 

 est. Finely divided iron was found to differ from cobalt 

 and nickel in its power of decomposing water, a phenomenon 

 which takes place slowly at ordinary temperatures, and rap- 

 idly at about 100 Centigrade. Iron thus resembles manga- 

 nese more closely than either of the other metals. 6 JB, 

 March 29, 788. 



OZONE IN THE LIBYAN DESERT. 



Professor Zittel, during a recent journey in the Lilian 

 Desert in Egypt, made some observations of atmospheric 

 ozone, from which it appears that the air over the desert is 

 richer in ozone than that at the oases and the valley of the 

 Nile, the ratios being as 73 to 48. The Libyan Desert, there- 

 fore, seems to be the richest in ozone of all portions of Eu- 

 rope. The ozone was observed to be always less in the day- 

 time than in the nicdit o-reatest during clear weather and 

 with northwest or west w T inds. Vegetation has been 2;ener- 

 ally looked upon as an important source of ozone, whereas 

 Ebermayer says that in all wooded regions the air in winter 



