CAR
CAR
( 88 )
10.25 measures in 200 of azotic impurity; 200.measures of the same oxygen were also deto-nated with 400. of hydrogen, and the wholewas reduced to 33 measures, so that 567 mea-sures had disappeared in the form of water.Of this, one jthird is the oxygen, amountingtherefore to 180, and if to this be added the10.25 of azote fofmd by the hydrosulphuret,the whole 200 of the oxygen employed will beaccounted for, except 0.75, which is too smallto be noticed. Hence the gas before combus-tion, consisted of
1669.8 measures of oxygen80. azote
1758.8
The gas after combustion amounted to1750.1. measures, from 100 of which thecaustic potash absorbed 63.42 of carbonic acid.Another portion of the same gas was detonatedwith a mixture of equal parts oxygen and hy-drogen, and the residue with potash to absorbthe carbonic acid always produced by the com-bustion of oxygen and hydrogen, arising (as theauthor asserts) from the carbonic impurity ofthe hydrogen. The diminution of volume andthe carbonic acid produced were no more thanwould arise from the hydrogen added to effectthe detonation, whence it is inferred that nohydrogen was elicited by the combustion of theplumbago. Another 100 parts of the gas re-maining after the experiment, examined hy hy-drosulphuret of potash, shewed 87 of oxygenand 13 of azote ; and another 100 parts of thesame gas detonated with 200 of hydrogen werereduced to 40, shewing 86.66 per cent, of oxy-gen and 13.34 of azote. Hence the composi-tion of the 1750.4 measures of gas remaining.after the combustion of the plumbago, is thefollowing:
Cubic centimetre*.
1110.1 of carbonic acid gas
557.06
83.24
oxygen gasazotic gas
1750.4
If the combustion of the carbonic acid is in-ferred from the quantity of oxygen gas requiredto produce it, it will be found that the volumeof oxygen gas consumed by the combustion is,.1669,8—557.1= 1J 12.7 cubic centimetres, ofwhich 7.3 are employed to oxydate the iron,leaving II 10.1 as the oxygen entering into thecarbonic acid produced. Hence converting themeasures to their equivalent weights, and addingthe weight of the plumbago consumed, the com-
position of 100. parts hy weight of carbonicacid will be 72.64 oxygen and 27.36 carbon.
If the computation be made from the weightof the plumbago consumed, and that of the car-bonic acid consumed, the proportions of 100.parts of this acid will be 72.61 oxygen, and27.39 carbon.
The combustion of box-v/ood charcoal con-ducted in the same manner, gave 72.85 of oxy-gen to 27.15 of carbon.
The charcoal of essential oil shewed 72.88oxygen to 27.12 carbon.
As no hydrogen appeared to be given out,either from the charcoal of essential oil, or fromthe plumbago, it would appear that these are theexperiments on which the greatest confidencemay be placed, and the mean of these gives forthe composition of 100. parts by weight of drycarbonic acid, 27.29 parts of carbon and 72.71of oxygen.
A second series of experiments on the com-bustion of diamond and other carbonaceousmatter has been undertaken by M. GuytonMorveau. d The apparatus employed by thiseminent chemist nearly resembled that ofMessrs. Allen and Pepys , and consisted of twogasometers connected by a tube, the centerpart of which was of platina and was passedthrough a furnace. The substance to be burntwas enclosed in the platina tube, and oxygen gaswas passed over it repeatedly from one gasome-ter to the other as long as the experiment lasted.
M. Guyton made the very important addi-tion of a tube filled with dry muriat of limeenclosed in each gasometer to absorb any mois-ture, and the gas immediately on entering andquitting the platina tube, was exposed to arti-ficial cold to enable it more compleatly to partwith any moisture which it might contain. Asthe oxygen was previously dried, any moisturecondensed in the tubes of muriat of lime wasInferred to arise from the generation of waterby the hydrogen of the substance burned, withthe oxygen employed. Hence this hydrogenwas estimated at T 74:-5tT§' of the increase ofweight acquired by the muriat of lime.
M. Guyton estimates the weighty of all the
f asses concerned to be as follows: the pressureeing 0.758 metre, (29.8432 Eng. inches) and12.5° cent. Ther. (54.5° Fahr.)
One litre ofDry Oxygen gas
-Common air
-Hydrogen gas
— Carbonic acid gas ■
weighs
Grammes.
1 34351.22471.19 870.10321.8372
A An. Chira. tom.-84,