514 . EE. P. TAYLOR. 
that values of friction are obtained under special conditions. 
By careful attention to brake design and modification of 
the methods of running a brake retardation test, the prob- 
able error in a measurement of the moment of inertia was 
greatly reduced, and the final results are given in the form 
of a table showing approximately the relative distribution 
of friction in internal combustion engines. 
Appendix. 
An idea of the kind of record produced on the chronograph, 
from which the retardations were calculated, may be 
gathered from Fig. 3. Hach stylus when unexcited marks 
a straight line beside the other. But when the contact 
maker for an instant closes the circuit round one of them 
it is caused to move suddenly to one side and back again, 
thus making a “‘kick’’ in the line. These kicks were 
arranged to move across the other line in order the more 
conveniently to compare the intervals marked on one line 
with those on the other. 
Revolution kick 
Fic 3. 
When interpreting: these records one of two methods was 
used, according to the length of the test. Ifthe test lasted 
for more than about seven minutes, every thirtieth second 
was marked and the number of revolutions which occurred 
