sphygmographs

It would be an interesting experiment if some professor of experimental psychology would arrange his class in the laboratory with sphygmographs on their wrists ready to record those pulse movements which accompany the sensation of 'thrill,' and would then introduce into the room without notice, and in chance order, a bishop, a well-known general, the greatest living man of letters, and a minor member of the royal family.

Human Nature in Politics Third Edition Graham Wallas 1895

After being flurried by clouds of paragrams about sphygmographs, and phonographs, and pneumatic telegraphs, and scores of other extraordinary scientific ways of communication, I'm not in the least surprised to learn that ants converse by one tapping another's head.

St. Nicholas Magazine for Boys and Girls, Vol. 5, Nov 1877-Nov 1878 Scribner's Illustrated Various 1868