Early English Pendulum Measures

Abstract

I FIND in a volume entitled “Metrology, or Weights and Measures of Great Britain and France”, by P. Kelly, “Master of the Finsbury Square Academy, London”, in 1816, a list of some of the old pendulum experiments of the last century, which contains some indications quite new to me. I am in hopes that if you will allow me space enough to make them known I may perhaps hear where further information is to be found. One of the measurements which he of course mentions is that of Graham. It is rather strange that though every one of the old writers mentions Graham's experiments confidently, I have hitherto failed to find any account whatever of those experiments. The other observers mentioned by Kelly—and so far as I know by him only—are “Emerson”, “Desaguillieres” [who always wrote under the name of Desaguliers], “Rotherham”, and “Sir Jonas Moore”. The mention is not a mere hearsay repetition of their names in this connection, as he gives the lengths found by each for London.