1816.] . during the Year 1815. A9- 
the number given by the experiments of Gay-Lussac, namely 
15614. 
_ The number for the weight of an atom of phosphorus is inac- 
curate. I shall hereafter give the true number deduced from 
actual experiment. 
__ The weights of the atoms of carbon and sulphur are the same as 
those I established. I believe them to be nearly correct. 
Dr. Marcet’s analysis of carbonate of lime is certainly very near 
the trath. By a very careful analysis I obtained 
MCANIEIC CIO Gi cleyetet storie eras cranes etre 
TAUHE Gis cen ve ed not fie oe oe tain cian ere 
100:0 
This I consider as a still nearer approximation to absolute pre- 
cision, I believe that in many experiments the weight of the acid 
has been under-rated, because a portion of it remained in the vessel 
in which the carbonate was dissolved. 
I do not consider the mode adopted by the author for determining 
the weight of an atom of sodium, iron, zinc, &c. as susceptible of | 
much precision. It consists in determining how much of these 
bodies is soluble in a quantity of muriatic acid capable of dissolving 
a known portion of carbonate of lime. The sources of inaccuracy 
are so numerous that they cannot be all guarded against. 
2. It has been long known to philosophers, that the bulk of air, 
and of all gases, is inversely as the pressure. We are in the habit 
in this country of ascribing the discovery of this law to Boyle. The 
French, on the contrary, ascribe it to Mariotte. I do not know 
which of these philosophers was really the discoverer of this law, 
because I have not in my possession the original dissertation of 
Mariotte, and do not know when it was published; but if it was 
published in 1666, as I have some reason for believing, the priority 
certainly belongs to Mariotte: for Boyle’s experiments were not 
published so early. When a body is in the gaseous state, the 
particles are at such a‘distance, that the attractions and repulsions 
which they possess have no sensible action, so that the distance is 
regulated solely by the repulsion produced by caloric, and by the 
external pressure. ‘This is evident ; forif a volume of oxygen gas 
be mixed with a volume of hydrogen gas, the mixture constitutes 
two volumes. Yet we know that there ‘is an attraction between 
these two gases. ‘Therefore, if the particles were within the 
‘sphere of each other’s attraction they would approach each other, 
and the bulk would be less than two volumes. M. Ampere has 
demonstrated that the resistance to external pressure made by any 
gas is directly as the number ot particles of the gas in a given bulk. 
This is precisely the law of Mariotte. 
8. Adhesion exhibits the characteristic marks of chemical affi- 
nity, and ought therefore tg be considered as a particular case of 
Bw 2 
