426 SCIENCE [N. S. Vou. XLVIII. No. 1243 
minum and iron, copper and iron and other 
combinations may be used, except that there is 
a loss in sensitiveness in the order indicated. 
Two pieces or strips # and EH’, each about 9.0 
mm. in width and 6.0 mm. thickness are riy- 
eted together and imbedded in solder V at the 
bottom of the casing. A screw W and lock- 
nut FR provide means of adjustment of the 
parts. This method of construction makes a 
rigid column which is not subject to the vibra- 
tions common in a laboratory. In practise, 
; the casing is filled with glycerin, which in- 
A—D creases the continuity of parts and prevents 
; corrosion of the metallic couple. 
The advantages of this design other than 
those already mentioned are apparent. First, 
the generous length of the metallic couple in- 
sures a maximum of sensitiveness. Second, 
this sensitiveness is further increased by the 
mechanical advantage of the lever. Third, 
continued movement of the bimetallic column 
in either direction imposes no strain upon any 
of the parts of the mechanism, a feature not 
incorporated in thermostats to be found on 
the market, and one which makes possible ac- ~ 
curate control with least adjustment for long 
and continuous periods of time. 
uw 
Ta 
He 
Ht 1 
Yooh = Aly 
A 
if 
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= 
Vn In the construction and testing of this 
eas) thermostat, the writer is indebted to the New 
il Mg Hampshire College and Experiment: Station 
if mi for the use of laboratories and equipment. 
eee | \ 
ia at C Cuas. H. Otis 
f=) BronocicaL LABORATORY, 
Lue WESTERN RESERVE UNIVERSITY, 
fetes CLEVELAND, OHIO 
| | i 
abe: 
i 
\ 
ae SCIENCE 
I | 
ik a A Weekly Journal devoted to the Advancement of 
id mt Science, publishing the official notices and pro- 
; aN ceedings of the American Association for 
the Advancement of Science 
Published every Friday by 
THE SCIENCE PRESS 
LANCASTER, PA. GARRISON, N. Y. 
NEW YORK, N. Y. 
Fig. 1. Entered in the post-office at Lancaster, Pa., as second class matter 
