-OF THE-

FRANKLIN INSTITUTE,

DEVOTED TO

SCIENCE AND THE MECHANIC ARTS.

EDITED BY

Chas. Bullock, Prof. Persifor Frazer, D.Sc., Prof. Edwin J. Houston, Theo.
D. Rand, Prof. Coleman Sellers, Committee on Publication :

VOL. XCIV.—JULY TO DECEMBER, 1887.

PHILADELPHIA:

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

1887.