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gen used was twice the measure of the ammo-nia : the whole was decomposed by a single ex-plosion ; and the hydrogen being estimated asequal to twice the bulk of the oxygen that disap-peared, ard the r siduary azote being measuredafter the removal of the remaining oxygen bysulphuret of lime, the composition of 100 mea-sures of ammonia was estimated to be 84.29 hy-drogen, and 15.71 azote, numbers far remotefrom those given byall theothermodes of analysis.

On the other hand, when the ammonia wasfired witha deficiency of oxygengas, 63 measuresof the former were exploded with S3 of oxygenholding 1. of azotic impurity. These werediminished to 57 by the first explosion, and nopert of the residue was absorbable either bywater or by sulphuret of lime, shewing that thewhole of the ammonia was decomposed, andthat all the oxygen employed had been con-sumed. The remaining 57. measures (consist-ing of hydrogen and azote) were detonated witha further addition of 40. of oxygen, and the re-sidue after this second detonation amounted to60, which was further analyzed by sulphuret oflime. By calculating as above, reckoning 2measures of hydrogen for every measure of oxy-gen actually consumed, it appears that the ori-ginal 63 measures of ammonia furnished by de-composition 31.34 of azote and 88.66 of hydro-gen, and hence 100. measures of ammonia wouldfurnish 73.88 of hydrogen to 26.12 of azote.

Dr. Henry gives the results of six experi-ments on the decomposition of ammonia with adeficient proportion of oxygen, but we musr con-fess that though they attest the care and fidelityof the experimenter, there is not quite sufficientagreement between them to lead us to place im-plicit confidence in this mode of operating, evenin the most skilful and practised hands. Theproportion of permanent gasses to the ammoniadecomposed, (the azot,e being actually mea-sured, and the hydrogen estimated by doublingthe oxygen expended 1 ) varies not inconsiderablyin the six experiments, the highest being I9S{,the lowest 180.2 fretn 100 of ammonia. Thisskews a correspondent variation of from 66 to72.2 cf oxvgcn required to saturate all the hy-drogen of 100. measures of ammonia, a variationwhich, however, i= probably not more than maybe expected in the best conducted experimentson such a complicated subject that requires sucha variety of precautions to ensure a tolerable uni-formity.

The author ascribes these variations chiefly tothe great difficulty of expelling all adhering

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moisture from every part of the materials andapparatus employed, and his general result isthat the proportion of oxygen most precisely ne-cessary to saturate 100. measures of ammonia is67|, (or 100. of oxygen to 148 of ammonia)and the 100 measures of ammonia will affordabout 136 measures of hydrogen and 47 of azote.

Dr. Henry also finds that ammonia will ex-plode with nitrous oxyd and with nitrous gas.

A series of experiments on the decompositionof ammonia has also been published by Mr. A.B. Berthollet / the principal object of them wasto examine a position hid down by Davy ,(which we shall presently notice) that ammoniacontains about T ’ T of its weight of oxygen. 1YI.A. B. Berthollet relates several experiments re-lative to the de-oxydation of iron in ammoniacalgas, and the decomposition of ammonia by itspassage through an incandescent tube; and byelectricity. In the latter method he gives as themean of six experiments, that 1. measure ofammoniacal gas dilates by electrization into

2 04643 measures of hydrogen and azote.

His general results are that 1 Hire of ammo-niacal gas is decomposed into 2.046 litres ofmixed gas, of which 1.545 is hydrogen, and0.146 is azote. The weight of this quantity ofhydrogen is 0.146 grammes, and that of theazote is 0.630 grammes, amt unting in the wholeto 0.776; and the weight of a litre of ammoniais 0.775 grammes, which agrees so nearly wriththe former as to demonstrate (if the data be cor-rect) that ammonia contains no oxygen, nor o'herconstituent part besides hydrogen and azote.It must be observed, however, that the experi-ments of this ingenious chemist (now no more)do not appear to have been conducted with thesame scrupulous attention as those of Dr. Henry.In particular, the means used for deprivitlg thegas of moisture were not so carefully attendedto; ami in the analysis by combustion withoxvgen, an excess of this latter gas was used,which produced so much nitric acid as sen-iblyto redden litmus, and thus to embarrass the re-sults. The presence of moisture will accountfor the greater expansion by electrization whichthis, chemist gives; for Dr. Henry uniformlyfound, when the ammonia was at the driest, thatthe expansion never quite doubled the originalvolume of the ammonia.

Mr. Dalton agrees with Sir H. Davy and Dr.Henry, that the volume of ammonia is notdoubled by decomposition, but that ICO. mea-sures of ammonia give from 185 to ISO of themixed gasses, the respective proportions of

licit, tom. 2.

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