208 STORRS AGRICULTURAL EXPERIMENT STATION. 
4 
By means of a worm gear fastened directly to the armature 
shaft the speed is reduced, a final regulation being made, if 
necessary, by a rheostat until the speed is such as to cause the 
stirrer to rise and fall about forty times per minute. ‘The con- 
nection between the motor and the stirrer is effected by means 
of a cord which is connected with the motor crank, passes 
upward to the ceiling or a shelf, over two pulleys, and thence 
down to the stirrer, as Fig. 4 indicates, although the pulleys 
are not shown. The cord permits the placing of the motor at 
_a distance if desired. 
To raise the fine iron wire to incandescence and thereby 
ignite the substance, requires a current of three to four amperes. 
If a r1o-volt current is available the necessary current may be 
obtained by switching it through four 32-candle power 110- 
volt lamps in parallel, as is shown in Fig. 5. In case a 55-volt 
current is used the 110-volt 32-c. p. lamps would be replaced by 
a similar number of 16-c. p. 55-volt lamps. ‘The use of lamps 
for resistance possesses the advantage that they are lighted for 
an instant during the heating of the wire and thus enable the 
operator to determine the time required for its fusion. 


Fia. 6.—PELLET PREss. 
Pellet press and mould.—The material to be burned is gen- 
erally pressed into a small pellet, so that it will easily be held 
in the small platinum capsule within the bomb. ‘This pellet 
form is advantageous also in insuring the complete combustion 
of all the material which, were it loose in the capsule, might 



