THE HAMILTON ASSOCIATION. 27 
-have begun with the investigations of the great French chemist, 
Lavoisier, about 1770. In order to show just how erude the 
science was in his time it may be of interest to recite one or two 
of his experiments. It was generally believed in his time that 
water is transformed into earth by boiling, because it was a mat- 
ter of common observation that whenever water is boiled for a 
time in a glass vessel a deposit of earthy matter is formed. In 
order to determtne whether a transformation takes place or not 
Lavoisier boiled some water in a closed vessel. He weighed the 
water and vessel and the deposit and found they were just the 
same as before. He therefore concluded that the deposit came 
from the disintegration of the glass vessel by the action of the 
boiling water. The history of the experiment does not say 
whether he used distilled water or not. If it was not distilled 
water the conclusion, though natural, was erroneous. He re- 
peated his experiments, weighing the vessel, the water and the 
deposit separately. He found there was just as much water as 
before, and that the weight of the deposit was exactly equal to 
the loss in weight of the vessel. 
This shows conclusively that the water he used was distilled 
water, and it proved beyond doubt that the water he boiled was 
not transformed into earth. Lavoisier followed these inves- 
tigations with further experiments and was enabled to give an 
explanation of the process of burning which up to this time had 
been a subject of study. The result of his experiments, which 
has entitled him to his eminent place in science, was to establish 
the fact that in all reactions the weight of the substances en- 
tering into action is in every case equal to the weight of the 
substances formed by the action. This is now known as the law 
of the indestructibility of matter. 
Innumerable experiments since Lavoisier’s time have served 
to impress this doctrine so firmly in the minds of scientists that 
it seemed to be a truth apart altogether from experiment. In- 
deed, Mr. Herbert Spencer, in his First Principles, went so far 
as to say that the doctrine of the indestructibility of matter has 
its foundation independent entirely of teachings of chemistry. 
