9G... 4 ore Incubation. 
covered with Pe ball of a dierinométer be png 
in eotwoks slang’ in this liquid, and swung in the air, (when 
the temperature of the room is ten degrees centigrade,) a 
diminution of volume takes place, corresponding with the 
is mode of cooling a been suites to the liquefaction 
of other gases. The gas is first dried by passing it through 
a tube containing mnriate of lime ; to this tube is adapted a 
tube bent at right angles ; the horizontal branch, swelling 
into a thin bail which is surrounded with cotton, and mois- 
me mercury, In this way the sathor has condensed chlo- 
° 
35. Artificial incubation.—An ingenious apparatus for this 
purpose has been invented by Mr. Barlow, near London, in 
which the requisite heat is maintained by the circulation of 
steam. It consists of a box or oven constructed of iron 
plates, divided into a great number of compartments, each 
of which is warmed to the temperature required. The eggs 
are first placed in that which is the least heated, and are 
mesually removed to that which is of the highest tempera- 
ture he more Aifficult part of the Aga consists 11 
exclude the steam by ‘the force of the heat itsell. It may 
ily be conceived that, in am apparatus containing fifteen 
eggs, aqueous vapours would arise so copiously as 
njure ihe success of the operation, had not means been 
debned: of absorbing them, A hydrometer of a particular 
construction is destined for this purpose. 
