will soften a metal sufficiently to allow it to be welded will, of course, render the various solders fluid.
The process is, moreover, on account of the extreme rapidity with which welds may be made, and the ability to concentrate all the heat at the point of union, a very economical one. Practical commercial work has shown that the cost of the coal burned under the boiler to produce the electricity is just about that of the coal used in a forge to do the work in the old way, and that the saving in time, and hence labor cost, is clear gain, to say nothing of the cleanliness of the process, the freedom from deleterious materials in contact with the metal, such as sulphur and ash, and the advantage of having the work always in clear view. How great the saving in time is may be appreciated by the following statement of actual work vouched for by Mr. Frederick P. Royce and cited in a paper read by him before the National Association of Carriage Builders:
Axle Welding.
| 1" | round | axle | requires | 25 | horse | power | for | 45 | seconds |
| 1" | square | " | " | 30 | " | " | " | 48 | " |
| 11⁄4" | round | " | " | 35 | " | " | " | 60 | " |
| 11⁄4" | square | " | " | 40 | " | " | " | 70 | " |
| 2" | round | " | " | 75 | " | " | " | 95 | " |
| 2" | square | " | " | 90 | " | " | " | 100 | " |
Tire Wedding.
| 1" | 3⁄16 | tire | requires | 11 | horse | power | for | 15 | seconds | |
| 11⁄4" | 3⁄8" | " | " | 23 | " | " | " | 25 | " | |
| 11⁄2" | 3⁄8" | " | " | 23 | " | " | " | 30 | " | |
| 11⁄2" | 1⁄2" | " | " | 23 | " | " | " | 40 | " | |
| 2" | 1⁄2" | " | " | 29 | " | " | " | 55 | " | |
| 2" | 3⁄4" | " | " | 42 | " | " | " | 62 | " |
The process, though only introduced into commercial work in 1888, has gone largely into use, and electric welders now form a part of the regular equipment of the carriage and bicycle factory, the boiler and tool shop, the wire mill, the yard of the shipbuilder, and the thousand and one establishments which have to do with the working and shaping of metals. It has been applied with marked success to the joining of the parts of railway frogs, of chairs to rails, and other heavy work, and in ordnance work, to the manufacture of shell and shrapnel. One of the most novel uses to which the process has been put is now to be seen in Boston on a section of the West End street railroad. This is the welding of the ends of the rails together without removing them from their places in the track, the object being to render the line of rails efficient return conductors for the current used with the trolley cars. To accomplish this the necessary apparatus is mounted upon a car provided with driving motors to enable it to
