Some Data on the Cost of Operating Automobiles for Commercial Purposes

Hiram Percy Maxim
1904 Scientific American  
shoe magnet. In order to register the wave form cor rectly, the galvanometer needle should move across the cylinder in a practically straight line, and, in order to diminish the arc, it is disposed as shown in the plan view. The galvanometer has a short needle attached to the movable part, while above and independently of it, is mounted a second and longer needle of alUmi nium, which is pivoted upon a heavy base outside' the instrument. and provided with a counterweight. The galvanometer needle
more » ... galvanometer needle has a vertical pin, P, on the outer end, which worl{s in a slot on the long needle, thus moving it back and forth, and the pen traces praCtical ly a straight line, as the swing does not exceed two inches. The mechanism which connects the drum with the motor allows it to register three complete wave periods during its revolution. The drum can carry a plain paper for simply observing the wave forms, or a strip of plotting paper for taking measurements. Each cycle is represented by an abscissa four inches long. At the rate of 40 cycles per second, the curve is traced in 25 seconds, and the paper moves under the pen at 23667
doi:10.1038/scientificamerican04231904-23666supp fatcat:mzqzqea36fgpxohjyf6iqgxbee