The enterprise. [volume] (Wellington, Ohio) 188?-1899, 1898-04-20

nearly as possible those believe to have
existed in connection with the Overman
test, its efficiency was 92.7 per cent.
Ny tests were all made with the Webb
dynamometcr, and with the assistance
of your engineers. This apparatus, which
Is extremely accurate and delicate, Is ex-
planned in detail in my report to you which
was published in the Iron Age" of Octohsr
21, 1897.
Regarding the Overman dynamometer
know but little, as your request that
might be allowed to witness Mr.. Overman's
tests was not acceded to by him.
Very respectfully,
(Signed) ]. e. DENTON.
Prof. Mechanical Engineering.
Letter from Prof. r. G. Carpenter, of
the Department of Experimental
Engineering, Cornell University, to
l.. A. w. Bulletin;
Ithaca, N. Y, March IA, 1898.
Dear Sir: My attention has been recently
called to an extract from a report of mine
in relation to the efficiency of bicycles,
which, from the heading of or from accom-
panying references is calculated to convey
the impression that the chain-driven bicy-
Gle is much more efficient than the chain
less The report in question, taken as a
whole will not, l believe, give the impress
sion that there is any material or sensible
difference. The report does show that the
chain-driven bicycle was on the whole
slightly. more efficient than the bevel-gear
driven machine, but this difference was
many times less than that due to tires OF
different construction and in many cases
less than that due to individual tires Of
the same kind and make. 1t follows from
the fact that riders have been unable to
detect the great difference which existed
in the friction caused by different tires that
they will be entirely insensble of the small
amount of difference which may be due to
the substitution of the bevel-gear as a
driving mechanism for the chain am,
Very Respectfully yours,
(signed) R.C. CARPENTER.
The letters presented herewith from
two such eminent authorities as Prof.
James L. Denton and Prof. r. c. Car.
penter, stamp as unfair and unwarrant-
ed the recent attacks upon the bevel-
gear chainless construction. made by
a manufacturer of chain-driven BIZ
cycles, through advertisements and dis
tribution of other literature.
The bit of inside history conveyed by
these two letters show how easily an
expert report if not given in full, may
be twisted to favor either side of sub
ject. AS soon as these unwarranted
deductions appeared in print, Prof. Car
penter publicly pronounced them un-
fair to him and to the bevel-gear chain
less construction. Prof. Carpenter
claims to find by dynamometer tests a
slight but insensible mechanical su-
periority for the chain. Prof. Denton,
in his article in the Iron Age" shows
that no superiority can be demonstrated
by dynamometer tests for either chain
or bevel-gears. Both agree that under
ideal conditions, by the dynamometer
the two mechanisms are practically
equivalent. Our experience, however,
demonstrates that this equality ceases
the moment the bicycles are put in ac-
tual service on the road. In a dynC-
mometer test the chain-driven bicycle
meets the most favorable conditions,
which do not exist for it on the
road. No bicycle rider need be told
that the moment chain and sprocket
is exposed to the weather the lubricant
begins to dry, the blocks and teeth to
clog with the dust and mud of the
road and deterioration commences,
Even if protected from the foregoing
influences, stretching will occur with
the best chains and sprockets, causing
back-lash and consequent inability OF
the rider to maintain straight track
in hill climbing, thus neccssitating
more eXertion. With the bevel-gear
chainless wheel, the high efficiency
shown by the dynamometer continues
indefinitely under actual service. Ow'
ing to the fact that its driving mechan,
ism is not affected by the weather OF
road conditions, and the further fact
that there is no back-ash, and conse
quently uniform pressure can be
maintained upon the pedals, this uni
formity of pressure giving the rider
perfect control of the wheel and en-
abling him to maintain a straight track
thus obtaining the benefit of every
ounce of applied power, the Columbi;
bevel-gear chainless, by this great say
ing of muscular energy, enables the
rider to ride at least ten per cent. far
ther with the same effort than he coulC
on the chain-driven bicycle. EXper
cycle engineers state positively that the
best bicycle chain and sprocket ever
made cannot retain their highest eff
cheney after 700 miles of riding, and
that the rider who desires to concerve
| power should not use the same chail
and sprocket for over 1000 miles o
riding. After $4,000 miles of road rid
ing a bevel-gear chainless bicycle ha
retained its highest efficiency. HOY
many more thousand miles of riding
the bevel gears would undergo withou
deterioration can only be conjectured
No radical change in bicycle con
struction has ever caused us so littl
trouble as Columbia bevel-gears. w
have had fewer complaints and fewe
difficulties than we have ever had witt
any new construction during our
years experience in bicycle building.