MR. C. V. BOYS ON THE RADIO-MICROMETER. 
IGI 
I have attached the circuit to the lower end of a very thin capillary glass tube 
about G cm. long, which hangs at the end of a quartz fibre, made by the bow and 
arrow process described in the ‘ .Philosophical Magazine ’ of June, 1887. Close to the 
Fig. 1. 
top of the glass tube is fastened a Very light galvanometer mirror, m, so that the heat 
which may fall upon it shall have no influence on the junction lower down (see fig. 1). 
The form of pole pieces which I have used is shown in figs. 2 and 3, which are a 
MDCCCLXXXIX.—A. Y 
