TRANSACTIONS OF THE SECTIONS. 57 
This second explanation will not bear the slightest examination, nor can it be made 
to tally with the results of the most elementary experiments relative to the conduct- 
ing power of the earth. - In fact, one cannot on this supposition explain why the 
resistance of the earth increases at first with the length of the layer; why it varies 
with the depth and the degree of moisture of that layer; why it changes if the mass 
of earth interposed between the two electrodes happens to decrease, or to be wanting, 
as I have proved by experiments made in mountainous districts; why the interposi- 
tion of a portion of earth of a different conducting power produces a variation in the 
‘resistance of the entire mass; why the resistance becomes infinitely greater when we 
keep this layer in a wooden trough separate from the earth, but in communication 
with it by means of large metallic plates. According to this explanation, the resist- 
ance of the metallic part of a mixed circuit ought to disappear, a thing which never 
happens. 
I think that I may be able to give a satisfactory explanation of the good conduct- 
ing power of the earth, founding my assertions on very simple experiments, and on 
theoretical views already known. As long ago as 1837, I proved, in a memoir 
published in the ‘ Annales de Physique et de Chimie,’ that in operating on a certain 
liquid mass, very considerable compared with the distance of the electrodes plunged 
in it,the length of the intermediate liquid stratum has no sensible influence on the in- 
tensity of the current. 
I have recently verified this result on a very large scale. I had a wooden case made, 
7 metres in the side; I keep this case isolated from the earth, and filled with water. 
Operating on this mass of water, we find that the resistance of a certain stratum of 
water, variable within certain limits, is independent of its length. In like manner, 
in studying the conducting power of spherical masses of water varying in diameter 
from 2 centimetres to 30 or 40 centimetres, I have found that the resistance of these 
spherical masses of water was the same, and independent of their diameter. 
I have already said, that this result may be deduced from the theory, and this is 
done as follows. From the same differential equations, given first of all by Fourier 
in his celebrated theory of heat, and which Ohm has ‘applied to electricity, suppressing 
in the latter case the terms which expressed the dispersion of heat in the air, are 
deduced in the case of the sphere, the results which 1 have obtained by experiments 
on the propagation of electricity in the earth. Although we are as yet ignorant of 
the physicai value of that variable U which figures in the fundamental equation of 
Ohm in three partial differentials, which is the same as that of Fourier in the propa- 
gation of heat, and although that equation would really be more applicable to the 
case of the metallic wire, which communicates at one extremity with the conductor 
of an electrical machine in action, and at the other extremity with the earth, than to 
the case of the electrical current defined by its electro-chemical and electro-magnetical 
action, it is no less true, that a certain number of the phenomena of the electrical 
circuit are explained by representing the propagation of the electrical current by the 
same equation given by Fourier in his theory of heat. Among these phenomena 
may be placed, the fundamental law of the propagation of electricity in metallic wires 
according to their section and length; and the other more general cases of the pro- 
pagation of the electrical current, and of derivation, in large metallic plates, or in 
spherical masses, and in the earth, such as they have been found by MM. Kirchhoff 
and Smaasen in Germany, and in Italy by my friends Ridolfi and Felici. 
On the presence of Carbonates in Blood. By Prof. G. 1. Muxper, of Utrecht. 
In this paper Prof. Mulder proves experimentally that blood contains carbonic acid, 
not merely in solution, but also in chemical combination with bases and organic sub- 
stances, as globulin, albumin, ἅς. When blood is mixed with water, boiled, filtered, 
and the clear liquid evaporated to dryness, and the residue redissolved in a little water, 
it will be found that acetic acid does not disengage any appreciable quantity of car- 
bonic acid, though carbonates are present in the blood. This circumstance, which led 
several chemists to infer that blood contains no carbonates, finds its explanation in 
the fact, that the presence of organic substances in the blood gives rise to the decom- 
position of the carbonates. In order to prove this experimentally, Prof. Mulder 
treated blood in the manner described, with the addition of carbonate of soda, but he 
