262 POPULAR SCIENCE MONTHLY 



well, Joule, Siemens, Matthiessen, Clark, Varley, Culley and others. The science 

 of the schools is so dissimilar from that of the practical electrician that it has 

 been quite impossible to give students any sufficient, or even approximately 

 sufficient, text-book. ... A student might have mastered Delarive's large and 

 valuable treatise, and yet feel as if in an unknown country and listening to an 

 unknown tongue in the company of practical men. It is also not a little curious 

 that the science known to the practical men was, so to speak, far more scientific 

 than the science of the text-books. 



Among Thomson's early discoveries was the fact that it was good 

 for students to do laboratory work. So almost immediately he was 

 appointed the professor of physics, at Glasgow, in 1846, at the age of 

 twenty-two, he " organized a laboratory corps from volunteer students," 

 and about 1849 he " established an incipient laboratory in the wine 

 cellar of an old professor's house," so his successor, Professor A. Gray, 

 tells me. In my time Thomson's laboratory consisted of one room 

 and the adjoining coal cellar, the latter being the birthplace of the 

 syphon-recorder. To avoid friction with the capillary glass syphon, 

 which was moved to the right or left by the electric signals coming 

 through the submarine cable, the end of the syphon was not allowed 

 to touch the strip of paper, but a continuous stream of ink spurted out 

 of the syphon on to this paper in consequence of the reservoir of ink, 

 into which the other end of the syphon dipped, being kept highly 

 electrified. 



To find out what sort of electrical machine should be used for this 

 purpose Thomson suggested that we should measure the efficiency of 

 frictional electric machines. We did so, and brought him the result 

 — viz., efficiency equals some small fraction of unity. He replied, 

 " I can not degrade a man by asking him to use his energy so waste- 

 fully ; I must design something better." And he did — viz., the influ- 

 ence machine; then when, by carrying out his suggestions, a fellow 

 student and I had constructed an influence machine and got it to work, 

 he sent us to the Glasgow Patent Office to see whether any one had 

 thought of that principle before. And we found Varley's and other 

 anticipations, with, however, this difference — that the earlier patentees 

 proposed giving to the arrangement an initial charge to start its action, 

 whereas Thomson's was a machine that worked on the compound in- 

 terest law, starting with an infinitely small initial capital. This led 

 not only to the " mouse mill " and the " replenisher," but to the class 

 working all kinds of problems on investments at compound interest. 

 " Now, suppose the interest is one one-thousandth per cent., paid every 

 one one-hundredth of a second, etc.," and we who had never invested 

 any money in our lives, indeed, possessed no money to invest, might 

 have been mistaken for budding pupils of a stock broker had any 

 visitor chanced to come into the lecture room. 



There was no special apparatus for students' use in the laboratory, 



