W A T
W A T
( 473 )
*» acidulous liquor, confiding of water with alittle nitric acid, the lo:s of weight in the wholeexperiment being only 33.9 grains.
I he mod fatisfaftory experiment, however,on this important fubjedt, was made in 1790,hy Vauquelin, Fourcroy , and Seguin. Theoxygen employed by them was procured fromoxymuriat of potalh, and the hydrogen from zincand diluted fulphuric acid : of the former the13475. 1 98 cubic inches, and of
fore laded fevernl hours, at the expiration ofwhich time there remained 987 cubic inches ofgas, confiding of the following ingredients, viz.467 Azot 465 Oxygen39 Carbonic Acid16 Hydrogen
987
amount was :
the latter ==25980,563 cubic inches: the com- The proportions of the gaffes that had difap-budion was carried on very flowly, and there- peared were edimated at
Hydrogen r= 25963.563 cub. inch = 1039.358 grs.
Oxygen a= 12570.942 (;ub. inch =r 6209.869 grs.
and the quantity of water produced was= 7245 g rs - which is as near an approximationto that of the gafles coniumed as can poffibly beexpedited in experiments of this kind. Thewater was fubjected to all the ufual chemicalteds, and appeared to be quite pure; thereremains therefore no poflible objection to theobvious conclufion from this experiment exceptthe appearance of the carbonic acid and azot in
Lavoifier . . . . 15.
Le Fevre Gineau . 15.2
7249.227
the refidual gas. Of thefe the former may beaccounted for by fuppofing that a little of thecarbon which zinc always contains, was takenup by the hydrogen and underwent combudiontogether with it: the azot was probably an ac-cidental impurity introduced with the oxygen.
The proportion of the ingredients that com-pofe water, as deduced from the precedingexperiments, are according to
of Hydrogen to 85. of Oxygen
84.3
85.66
The only objection that has been urged*gaind the above proof of the compofition ofwater is the following by Dr. Priedley. Thisphilofopher having concluded, upon as we thinkmfufficient grounds, that the greated part of theponderable portion of all gaffes is water, main-tained that in the combudion of oxygen andhydrogen gas the water that appeared wasmercy precipitated, and that the real oxygenand hydrogen combined together, forming therefidual azot or nitric acid according to circum-flances. To this however it may be replied,that the oxygen from manganefe, and frommod of the other fources from which it is pro-cured, may readily be proved by the common■eudiometrical proceffes to be mixed with a fmallcontamination of azot; that Mr. Cavendifh andothers have very fatisfadlorily proved that theproportion of nitric acid or azot obtained de-pends wholly on the previous impurity cf thegafles employed ; and thirdly, that accordingto Dr. P s. hypothefis, real oxygen and hydro-gen mud be both of them entirely imponderablefubdances, for in thofe cafes where no nitricacid appears after the combudion of the twogafles, but only a fmall portion of azot, hemud fuppofe n^t only that this fmall refidue ofTOL. II.
azot contains the whole of the real oxygen andhydrogen, but that as this azot dill retains itsgafleous form it mud dill confid almod entirelyof water.
The effedbs of ele&ricity on water ferve as afurther proof of the modern dodtrine relative toits compofition : by palling fliocks along an in-terrupted golden or platina wire immerfed inwater, bubbles of gas are obferved to be difen-gaged at every explofion, and when a quantityof air has been thus colledled, if an eleddricalIhock is palled into it, an explofion immediatelyfucceeds, water is formed, and the gas difap-pears, with the exception of a minute portionwhich is probably atmofpheric air previouflyheld in dilution by the water.
The aftion of certain of the metallic bodies,when heated, on deam palled over their fur-face, was fird adduced by Lavoifier as a proofof the decompofition of water, and his deduc-tions have been acquiefced in hy mod fucceed-ing chemifts. A quantity of loft iron wirebeing put into a glafs tube and heated red hot,
100 grs. of water in the form of deam wereflowly palled into the tube; the water dilap-peared, 416 iu>ic inches of hydogen gasweighing 15 grs. were produced, and the iron3 0