For an easy and striking lecture experiment, I employ a tube open at both ends and bent like a W. The two open arms are short and the platinum wires are fixed at the highest bend. The tube is filled with hot mercury--one of the ends being closed by a caoutchouc stopper for the purpose--and a dry mixture of 5 volumes of air and 2 volumes of carbonic oxide is introduced into the bent tube over the mercury. A little phosphoric oxide is passed up one arm. After a few minutes the gases may be submitted to the spark without exploding. A little water may then be introduced through a pipette into the other arm; and if the spark is passed directly the gases ignite in the wet and not in the dry arm of the tube. The admixture of the inert nitrogen renders a larger quantity of aqueous vapor necessary for the explosion than when only carbonic oxide and oxygen in proper proportion are present. * * * * * COMPOSITION OF BEERS MADE PARTLY FROM RAW GRAIN. At the present time English brewers are being denounced for substituting properly-prepared maize, rice, and other raw grain for barley malt, and the beers produced partly from such materials are described as being very inferior, and even injurious to health. That such denunciations are altogether unwarranted is evident to all who have paid any attention to the subject, and are acquainted with the chemical changes involved in brewing, and with the composition of the resulting beers. Unfortunately but few comparative analyses have been published of beers made solely from malt and beers made from malt in conjunction with raw grain, and therefore such wild assertions as were recently uttered in the House of Commons have remained unanswered. A German chemist, J. Hanamann, some time since made a series of analyses of beers brewed partly from raw grain, and his results completely controvert the theory that raw grain beers essentially differ in composition from malt beers. Four worts were made by the decoction system of mashing: A entirely from barley malt; B from 60 per cent. of malt and 40 per cent. of maize; C from 60 per cent. of malt and 40 per cent. of rice; and D from 60 per cent of malt and 40 per cent. of pure starch. The analyses of these respective worts gave the following results: A B C D Sugar............... 4.96 4.08 4.84 4.87 Dextrine............ 6.05 6.83 6.35 6.60 Total extract....... 12.29 12.27 12.30 12.32 Albuminoids......... 0.82 0.78 0.68 0.42 Other substances.... 0.46 0.58 0.43 0.43 It will be seen that these worts vary very little in composition, the chief points of difference being that those made partly from raw grain are more dextrinous and contain less albuminoids than the wort made from malt alone. The process of brewing was then continued as usual, and after fermentation the resulting beers were again analyzed with the following results: