ZOOLOGY AND BOTANY, MICROSCOPY, ETC, 
515 
stiff wire communicates tlie motion of the capsule to the lever M, and 
this lever is so connected with the tube C, that when the capsule expands 
the tube moves horizontally to the left. At the side of the apparatus is 
a lantern containing an open boiler F, heated by quite a small gas or 
petroleum lamp-flame. The bottom of the boiler is connected with the 
bottom of the water-jacket by a tube, so that the water in the boiler 
always stands at the same level as that in the water-jacket. The bottom 
of the ice vessel B has also an outlet which communicates with the 
water-jacket above the incubating chamber. The water-jacket is pro- 
vided at the top with an overflow and waste-pipe at N, through which 
the surplus water escapes. The front end of the little tube C is bent 
downwards, and immediately under the bent end are two tubes D and E, 
Fig. 47. 
standing vertically side by side in an open vessel, with a short interval 
between them. The vertical tube E is connected with the top of the 
ice-box by a tube E', and the vertical tube D is connected with the 
boiler F by a tube D'. The valve K is connected on the right with a 
continuous water supply, and on the left by means of a small indiarubber 
tube with the small tube C. The apparatus having been adjusted accord- 
ing to the instructions, the action is as follows The stream of water 
passing the valve K, flows along the tube C, down the tube D, and alono- 
the tube D' to the boiler F, where it is heated, and thence flows into the 
water-jacket, and increases the temperature. After a time the capsule 
expands and moves the tube C to the left, thus causing the water to fall 
between the two tubes D and E. In this case the water is collected in 
the open vessel in which the tubes D and E stand, and is conducted by 
the pipe H H' to the waste-pipe N, without producing any effect what- 
ever on the incubating chamber. If the temperature of the room in 
which the incubator is placed is above the boiling-point of the capsule. 
