682 KANSAS CITY REVIEW OF SCIENCE. 
only necessary to draw vertical lines dividing this distance into twelve equal parts, 
each one of these will then represent five minutes. 
After determining upon the principles it became very easy to work up the 
details that would place the instrument in a convenient form for manufacture and 
use. These may be seen, as applied, in figs. 7 and 8. Fig. 7 is a front elevation. 
of the complete thermograph. 
Fig:8. 
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It consists of a cast-iron case having two departments, one for the recording 
mechanism and actuating clock movement, the other for the battery. In the 
upper part of the front there is a circular depression for the reception of the ther- 
mometer proper or perceiving portion of the instrument when not in use. 
This is held in place by means of two little catches, one on either side, as 
seen in the figure. On both sides of this are the binding posts for the reception 
of the wires leading from the thermometer proper, when the latter is in position 
in the axilla. The open work in the lower portion is intended for the ingress of 
air and egress of gases. Fig. 8 is an interior elevation with the front removed; 
above is seen the recording mechanism, and below the thermo-electric battery. 
This form of battery gives a continuous and unvarying current, requires no clean- 
ing or recharging, and costs but little to run, hence it is the most available source 
from which to derive the current; the heat for operating it may be supplied by 
either an alcohol lamp or gas-burner. Not only is it possible with this instrument 
