An Apparatus for Calculating Efficiency (1883)

C. Vernon Boys, "Meters for Power and Electricity", in Nature, 14 June 1883, vol 28 #711, pp 162-5 in the weekly issue of pp 145-168.  Original self-wrappers, removed from a larger bound volume. Crisp and clean copy. $95  This is from Boys' lecture at the Royal Institution, March 2, 1883.  

C. Vernon Boys (1855-1944) was a British physicist and fine experimentalist and contributed this exemplary instrumentation article which appeared in the journal Nature (14 June 1883), when the no-longer new-ish journal rapid-published the breaking and thoughtful science news of the day every week.  Generally articles in the early decades would seldom range over two pages--of course, the pages were dense, and in two columns, with usually 80 lines per column and ten words per line, so each page could be filled with 1600 words, which is four times the general length of a novel.  In any event Boys' article ran five columns, or about 5,000 words, which is a fairly meaty article.  

From Gaston Tissandier's Popular Scientific Recreations (1883):

Mr. C. Vernon Boys has exhibited and described a very ingenious new 
integrating machine of his invention, and its application as a measurer of the 
electric energy in the circuit of an electric lamp or a dynamo-electric motor. 
Mr. Boys' mechanical integrator belongs to the class termed tangent machines, 
and consists essentially of a small disc or wheel running along the surface of 
a drum or cylinder. When the wheel runs straight along the drum parallel 
to its axis there is no rotation of the latter, but when the wheel is inclined 
to the axis the drum rotates, and the integral is represented by the amount 
of rotation. Continuous action is secured in giving the drum a recipro- 
cating motion along its axis, so that when the wheel has travelled to one end 
of the cylinder it can travel back again. The new integrator is especially 
adapted for measuring forces which are either delicate or variable. It is 
applied by causing the varying force to be measured to vary in a correspond- 
ing manner the inclination of the wheel to the axis of the rotating cylinder.

Some of Boys' papers on calculating and measuring machines include:

• “An integrating machine.” Proceedings of the Physical Society of London, 4:199–206, 1881.

• “On a machine for solving equations.”Proceedings of the Physical Society of London, 7:355–360, 1885.

• “A new analytical engine.” Nature, 81(2070):14–15, 1909

• “Apparatus for calculating efficiency.” Proceedings of the Physical Society of London, 5: 28–35, 1882a.

• “On integrating and other apparatus for the measurement of mechanical and electrical forces.” Proceedings of the Physical Society of London, 5:8–28, 1882b