89
Was it a silk apron which exhibited electric sparks? Silk was then scarce.
90
The Italian fire-fly.
91
This last is found to be the real reason, air not being a good conductor, and therefore not allowing the escape of heat. The confined air is disengaged when these substances are placed under an exhausted receiver.
92
This is erroneous. Air, in fact, is one of the worst, and metals are the best conductors of heat.
93
See No. 28 in the table of the degrees of heat.