392 /Scientific Intelligence. 



property of slowly fixing free atmospheric nitrogen. This prop- 

 erty is independent of nitrification as well as of ammoniacal con- 

 densation. And since the compounds formed are complex and 

 insoluble amides of the character of those existing in living 

 animals, it must be attributed to the action of living organisms. 

 It is not manifested in winter, but is operative throughout the 

 season of active vegetative growth. A temperature of 100° 

 destroys it. It goes on as well in a closed vessel as in contact 

 with the atmosphere ; as well in the free air at the top of a tower 

 as under cover in the vicinity of the soil covered with vegetation, 

 or within a closed room in the interior of a building. It takes 

 place in the dark though less actively than in the light. The 

 figures obtained show that the amount of nitrogen which would 

 be fixed by one hectare of surface would be, during a single 

 season, for a yellow sand 20 kilograms; for a second sand 16 to 

 25 kilograms; for a clayey soil 32 kilograms. — Bull. Soc. Chim., 

 II, xlv, 121, February, 1886. a. f. b. 



5. On the Combustion of Carbon monoxide and of Hydrogen. 

 — In 1880, Dixon showed that a mixture of perfectly dry carbon 

 monoxide and oxygen did not explode by the electric spark; but 

 that even a minute trace of water or of a volatile body containing 

 hydrogen, rendered the mixture inflammable. He accounted for 

 this result by supposing the steam present to act as a carrier of 

 oxygen, itself undergoing reduction thus: (l) CO + H 8 = C0 8 

 + H and (2) (H 8 ) 8 +0 8 = (H 8 0) 8 . To settle, if possible, the 

 question as to the mode in which the steam acts he has now 

 published a new series of experiments. He finds for example 

 that small quantities of H 2 0, H 8 S, H 4 C 8 , H 8 C0 8 , H 3 N,H 18 C 5 , 

 HC1 invariably cause the explosion, while S0 8 , CS 8 , C0 8 , N 8 0, 

 C 8 N 2 and CC1 4 do not. Hence he concludes that the steam does 

 not act simply as a mere third body, but in virtue of its own 

 peculiar chemical properties. He then studies the two reactions 

 above given. As to the reduction of steam by carbon monoxide^ 

 that fact was established by Grove in 1846, when he discovered 

 "the curious reversal of affinities." Dixon's experiments were 

 conducted in a eudiometer containing two platinum coils. When 

 carbon-monoxide and steam were heated to dull redness for six 

 hours 5'2 volumes of CO were oxidized and 5-2 volumes of H pro- 

 duced, out of 100. At full redness for the same time 1T7 per- 

 cent and at bright redness 14-3 per cent of the CO was converted 

 into C0 8 . When C0 8 and H were subjected to the action of the 

 hot platinum in the same tube, practically the same state of 

 equilibrium was reached. If, however, the C0 8 formed in the 

 first case, or the H 8 in the second, be removed as fast as pro- 

 duced, then the oxidation of the CO in the one and the reduction 

 of the C0 8 in the other become complete. Induction sparks pro- 

 duce in both cases similar results. When the quantity of steam 

 present is increased, the amount of CO oxidized is also increased. 

 At a vapor tension of 13 ram , 3 percent, at 102 mm 11'6 percent 

 and at 214 mm 21-4 per cent of hydrogen was formed. Having 



