1816.] Gascous Bodies and the Weight of their Atoms. 345 
Set Third—Bodies having the weight of their atoms four times 
the specific gravity of their volumes :— 
Sp. gr. oxygen being 1. Weight of an atom, 
Mydrodie acid’ 22/2 022 )3°986 oN 1944 
Muriatic acid.......... pI BS ye peak Pa RS: Phe 4°623 
Nitrous gas...... ROR OFS 75 ieee ese 3°750 
Hydro-cyanic acid...... O84S3 ies cae 3°3732 
MUMPMAINITIA” '. 5.) k ale't we rs 5s LP ll SR ln 2°125 
From these tables it is obvious that there exists a very simple rela- 
tion between the specific gravity of gaseous bodies and the weight 
of their atoms. “he weight of the atom is either equal to the 
specific gravity of the gas, or twice that weight, or four times that 
weight. It seems to follow from this that the ultimate atoms of 
bodies differ in their weight, and that the ratio of their weights may 
be determined by the specific gravity. 
The specific gravity of olefiant gas is twice as great as might have 
been expected. Hence it is obvious that the volume of carbon and 
the volume of hydrogen, of which it is composed, must _be reduced 
to half a volume. ‘This is not the case with any of the other binary 
compounds. This is the reason why the weight of its atom appears 
equal to the specific gravity of the gas. 
The atom of all the simple substances (oxygen excepted), namely, 
chlorine, sulphur, azote, carbon, and hydrogen, is' double the specific 
gravity. ‘This is the law which Dr. Prout pointed out as belonging 
to all bodies. It will probably be found to apply to all simple bodies 
except oxygen. ‘The weight of an atom of carbon and of sulphur 
was obtained by subtracting the specific gravity of oxygen from that 
of carbonic acid, and the specific gravity of hydrogen from that of 
sulphureted hydrogen; because it is known that oxygen may be 
changed into carbonic acid, and hydrogen into sulphureted hydrogen, 
without undergoing any alteration in their bulk. 
The composition of the compound bodies belonging to the 
second class is as follows :— 
Sulphurous acid, composed of 1 vol. sulphur + 1 vol. oxygen. 
GCapponic guid 2. 6.5.0 ies. 1 carbon + 1 oxygen. 
Nitrous oxide ..........6-.. 1 azote + 4 oxygen. 
Carbonic oxide ............ 1 carbon + 4+ oxygen. 
ee ee vouk hydrog. + 4 = oxygen. 
Sulphureted hydrogen........ 1 sulphur + 1 hydrog. 
Carbureted hydrogen ........ I carbon + 4 _ hydrog. 
Cyanogen .. is cides eviccvewecs 1 carbon + + azote. 
These fractional numbers disappear when we consider these com- 
pounds as composed of atoms, in consequence of the weight of the 
atom being double that of the volume. 
The first four compounds of the third set consist of gaseous com- 
pounds which unite without undergoing any condensation. ‘Of 
Vor, VU, N° V. 
