Note 51 — COMPARATIVE EXPERIMENTS.

This experiment is very interesting in two or three respects. A neck of half the usual length—with only four bendings—sufficed to preserve the fluid for several days; and when this fluid (which had been in the bent-neck apparatus for nine days) was sealed up in the same flask during ebullition, it remained in vacuo for thirteen days without undergoing any apparent change, and then only became turbid under the influence of a higher temperature. Yet some of the same fluid, in a flask which was hermetically sealed during the first ebullition (No. XV.) behaved as such an infusion usually does, and became quite turbid in forty-eight hours.