Marine Iron Works. Chicago. Catalogue free. C. S. metal polisb. I n d i an a polis. Samples free. Presses & Dies. Ferracutp. Mach. Co., Bridgeton, N. J. Screw machines, milling macnines, ana drill presses. The Garvin Mach. Co. , Latent and Canal Sts.. New York. Use the Hougb Security Cash Recorder. Entirely different from a Cash Register. Hough Cash Recorder Co., South Butler, N. Y. The best book for electricians and beginners in electricity is llJxperimental Science, by Geo. M. Hopkins. By mail. $4; Munn & Co .. publishers, OOl Broadway, N. Y. 5th ed ition Thompsons Dynamo Electric Machinery Thoroughly revised. rewritten up to date; with new iIIus tratlon s. $5.50. :Spon & C h am berlain, 12 Cortlandt St., New York. JSend for new and complete catalogue of Scientifl c and other Books for sale by Mann & Co. , 361 Broadway, New York. Free on application.