404 Dr . Hulme's Experiments and Observations 
When the whole apparatus was put in use, the phial was 
filled with cold pump water, in a pneumatic tub, then inverted, 
and the species of air to be employed was let up into it, to 
the quantity of about eight ounces. The subject for experi- 
ment being applied to, or fastened upon, the top of the cork, 
the stand was placed on the tea-saucer, and then introduced, 
under water, into the phial containing the air. The whole ap- 
paratus, being now supported by the tea-saucer, with water in 
it, was deposited in the laboratory for experiments on light. By 
this contrivance, the experiments were made in about eight 
ounces of air, by measure, confined above two ounces of water. 
§ i- 
The Effects of common or atmospherical Air on spontaneous Light . 
EXPERIMENTS. 
Exper. 1. Two fresh herrings were hung up together in the 
laboratory, so as to touch each other at their flat sides ; and it 
was observed that the parts in contact remained dark, while 
those exposed to the open air became very luminous. 
Exper. 2. Another fresh herring was laid upon a piece of 
thick brown paper, and placed in the laboratory. On examina- 
tion, the next evening, the upper part, which was exposed to 
the air, was very lucid ; but the underside, lying upon the paper, 
remained quite dark. 
Exper. 3. A luminous herring was divided transversely quite 
through its middle fleshy part; but the inside was perfectly dark. 
On the following night, that which before was dark had become 
luminous. 
