PHILADELPHIA 
6a$ Regulators 
(THERMOSTATS) 
LenU's Latest Gas Regfulator. — This regulator is original 
with us, and is considered the most practical inexpensive 
regulator made. 
The bulb containing mercury is placed through tubula- 
ture in the air or water space of incubator. The inlet 
tube A is connected by means of rubber tubing to the gas 
^ supply. The outlet tube E is connected in the same manner 
with the burner under incubator. The gas enters at A, 
passes through the large aperture B, then down through 
the hollow T-shaped stopcock and over the surface of the 
mercury at F, and thence to the burner through the outlet 
tube E. When the temperature in the incubator tends to rise 
higher than that at which the bacteriologist has adjusted the 
regulator, the mercury in bulb expands till it closes the opening 
at F. The only course then left is through the small aperture in 
the side of stopcock C and downward through a narrow groove 
D in the interior of collar or bushing of stopcock immediately 
adjacent to this small aperture, and thence to the burner. 
The aperture available for the gfas to pass can be reduced to 
any size desired by slightly turning the stopcock to the right 
or left of the median line. With a minim or small Koch bunsen 
burner the size of the reserve flame (which is to prevent the 
flame going out entirely) can be reduced automatically to 
inch in height, or the stopcock can be adjusted for the reserve 
flame of a larger burner just sufficiently to prevent it striking 
back and igniting at the air inlet. A most important feature 
of this regulator is that the tubes A and E are rigid and im- 
movable, so that there is no danger of their shifting from the 
C weight of attached rubber tubing. The incubator is kept 
stationary at any desired thermal point by adjusting the 
plunger at side. 
The screw of the old Reichert regulator has been discarded 
e" and in its place there is a glass rod plunger (with knob at end 
for convenience in manipulating). This plunger works in a 
stuffing box, which is securely packed and is adjustable, so that 
there can be absolutely no leakage of mercury. 
By slowly pushing in the rod with a slightly rotary motion 
the mercury is displaced, and rising, closes the aperture at 
bottom of T stopcock sooner and lowers the thermal point. 
The thermal point is raised when desired by pulling out the 
plunger slightly. Made in two sizes, small, for water baths, 
etc.; large, for incubators and sterilizers, each $3 50 
This regulator is very sensitive, and will regulate the tem- 
perature of an incubator automatically to less than )4° C. There 
is about eight times the quantity of mercury in bulb that is usu- 
ally employed. 
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