Correspondence. 267 
ister the changes of direction in a vessel for every 3 minutes during 
the 24 hours. The marking is made on a compass-card ; and it e 
bles the captain to control with certainty the direction followed by his 
ship, and overlook most effectively the maneuvers of the steersman and 
This self-register consists of 3 principal parts; 1, a clock-movement 
placed at the center of the apparatus, for causing the point or pivot 
he fire ha 
~~ Stat progress, and threatened a complete destruction of the 
buildings d be had. is cri resen 
: 1 
engine, and immediately the steam penetrated through the work-shops, 
the fire Was seen to diminish, and soon was reduced to so trifling an 
Sxtent that it was easily mastered when aid arrived. ut 
ls fact cannot have too great publicity ; and it is especially im- 
Portant that manufacturers, captains of vessels, and superintendents of 
Work-shops should be familiar with it. . 
On read.—It is generally admitted that fresh bread differs from 
ht, when stale. 
M. Boussingault has recently shown that the difference between the 
a id stale condition is not due to a diminution of the water, but to 
Peculiar molecular condition which takes place on cooling, and which 
Thenard a8 long as the temperature remains below a certain limit. M. 
dtate whi pains: this. transformation by considering the bread a hy- 
Which heat softens, and a low temperature hardens, or renders 
