Our thanks are due also to Prof. C.H. Chandler, Ph.D., of the Columbia School of Mines, for the Analyses of the Springs, and for electroplates and valuable suggestions from the American Chemist, of which he is the distinguished editor.
We would acknowledge here also, the assistance and uniform courtesy which we have received from the Superintendents and officers of the various Springs. The failure of an engraving company to fulfill their agreement has delayed the issue of the work and prevented the insertion of several other engravings.
R.F.D.
Saratoga. June, 1872