804 ON THE SHRINKAGE AND EXPANSION OF CAST IRON .

The phenomena of the 2nd cast were not so marked.So much is the human body the child of habit, that Ineither felt the same extent of sensation, nor remarkedit upon the workmen, although the thermometer main-tained itself for some minutes at 158°. In the afternoonthe air began to circulate, and the temperature of theshop became much more moderate. The 3rd cast, ho’w-ever, soon destroyed this pleasant change, and, beforehalf done, the thermometer rose to 164°. Still theworkmen seemed to suffer less than in the morning, ex-cept on the legs. Most of the ranges of large mouldswere throwing off the caloric in ruelle undulations, andexhibiting symptoms of approaching redness. Thesmallness of the shop admitted only of 2 J feet of pas-sage betwixt range and range, which made the tempera-ture of this spot intolerable.

When the cast was finished, I had the doors and win-dows shut. This made the real state of the moulds vi-sible. The 18, 24, and 32-pounders were all of a darkglowing red heat, and presented an arid and inhospitableglare, with which it was impossible long to exist.