Steam Engines. — . 203 
Tae royal printing office, which employs 80 presses, 295 
workmen, and from 70 to 80,000 reams of paper, is not in- 
cluded in this estimate. 
f the books printed annually in France, it is estimated 
that there are of theological works seven per cent., of juris- 
oe five, arts and sciences twenty, politics sixteen, 
elles-lettres twenty-eight, and'history twenty-four.— Bulletin 
des Sciences, Geographiques, Statistiques, &c., Mars 1824. 
51. Rapid evaporation.—Professor Oersted has pointed 
out a method of considerable utility in the evaporation of 
liquids. He fastens together a great number of fine metallic 
rods, or wire, and puts them in the bottom of the distillery 
or evaporating vessel, and by this means he distils seven 
measures of brandy with the same fuel, which without the 
rods would distil only four.—Budlletin des Sciences, Phystques, 
&c. Avril, 1824. 
52. Steam Engines.—The French Institute have subjected 
to a careful investigation, the various circumstances connect- 
ed with the explosion of steam boilers, and an ordinance of 
the king, founded most probably upon the conclusions of the 
Academy, decrees: Ist. That no high pressure engine shall 
be established without alicense. 2d. That every proprietor 
shall declare before the proper authority, the degree of pres- 
sure with which his machine is intended habitually to act, 
3d. That no high pressure engine shall be erected without 
having its strength previously determined by the hydraulic 
press, that every boiler shall be able to sustain five times the 
force under which it is to act, that the intended pressure shall 
be stamped upon it, and that no boiler shall be erected until it 
receive this stamp. 4th. That two safety valves shall be 
adapted to each boiler, so large that either of them can dis- 
engage the steam with sufficient rapidity, one of them to be 
at the disposal of the fire man, and the other covered with a 
grating, locked, and the key kept by the proprietor. Sth. 
That two round plates shall be inclosed in the boiler, one of 
which to be at least equal in diameter to the safety valve, 
and to be composed ofa mixture of metals which will melt or 
soften at a temperature of 10° centigrade, above that of the 
boiler; the other of double the diameter, inserted near the 
locked valve, and of such a composition as to soften at 20° 
