THE JOURNAL

OF THE-

FRANKLIN INSTITUTE,

DEVOTED TO

SCIENCE AND THE MECHANIC ARTS.

EDITED BY

Prof. Edwin J. Houston, A.M., Ph.D., Chairman; Prof. Arthur Beardsley,
C.E., Ph.D., Mr. Theo. D. Rand, Prof. Coleman Sellers, E.D.,
Mr. J. C. Trautwine, Jr., Committee on Publications,

with the Assistance of Dr. Wm. H. Wahl,

Secretary of the Institute.

VOL. CXXXVIII.-Nos. 823-828.

JULY-DECEMBER, 1894.

PHILADELPHIA:

Published by the Institute, at the Hall, 15 South Seventh Street.
1894.