CHEMISTRY. 221 



A current of sparks through marsh gas augments its volume rap- 

 idly, with deposition of carbon. One hundred volumes became in 

 two minutes 127, in 10 minutes 154; but still for complete action 

 hours are necessary, the maximum final volume being 181. On 

 the old view that free C and H are formed, the volume should 

 have been doubled. Nevertheless, in 1860, Burr and Hotfman ob- 

 tained results similar to the above, which they inferred to be due 

 to impossibility of complete decomposition, not knowing of the 

 formation of acetylene." Berthelot's results show the surprising 

 fact that but one-eighth of the original marsh gas can really 

 be converted direct!}' into its elements. After some hours, when 

 no further carbon is deposited, the residual gas contained 13 or 14 

 volumes of acetylene, showing that half the marsh gas has under- 

 gone the following reaction : 2C2 H4 = C4 H2 -{- 3 H2. But on 

 removing the acetylene now by absorption, it is found that a new 

 state of equilibrium is established, and the amount rapidly in- 

 creases again, the final amount of acetjiene producible (39 vol- 

 iniies), proving a transfoimation, by the above reaction, ot'four- 

 Jifths of the marsh gas (as the condensation, from marsh gas into 

 acetylene, is to one-half; the latter containing its own volume of 

 hydrogen) . Hence a far easier mode of pn.'paring acetylene than 

 heretofore known. Common coal gas may be passed slowly 

 through a tube permeated by a current of sparks, and then 

 through an absorbent of acetylene. 



The 39 volumes of condensible matter above is not wholl}^ rep- 

 resented, however, by acetylene. Tiie latter, as Berthelot has 

 proved, is gradually condensed by heat into hydrocarbons of 

 heavier molecules, and the heat of the spark converts it partially 

 into benzole (vv'hich is triacetijlene CioHg = C4 Ho, C4 Hg, C4 Ho) 

 and still heavier hydrocarbons, some of which are even tar-like 

 and precipitate with the carbon. The action of the spark thus 

 assimilates itself to that of simple heat, the first transient action 

 of which, on marsh gas, according to previous researches of Ber- 

 thelot, is to produce acetylene, which is then gradually condensed 

 by prolonged action. — Am. Gas Ligjit Journal, 



RELATIVE PROPORTION OF ALKALIES FOUND IN THE ASH OF 



DIVERS PLANTS. 



The same plants grown near the sea, an^il at remote distances 

 therefrom, alter their saline constituents, so that, while growing 

 near the sea, soda prevails, as a ruli;, over potash, the reverse 

 being the case while the same plant vegetates at a distance more 

 or less remote from the sea; of this fact some instances are given 

 in tins paper. The relation of the soda to the potash of the ash 

 of Crambe maritima, when grown near the sea, was as 960 to 

 1,000; when grown at Paris, as 89 to 1,000. The relation of 

 soda to potash in the ash of black mustard seed grown near the 

 sea was as 200 to 1,000, while when grown in Paris it was as 96 

 to 1,000. — Bulletin Mensuel. 



19* 



