Paper, 'On the heating effects of electric currents. No. III' by W H [William Henry] Preece Preece writes: 'I have taken a great deal of pains to verify the dimensions of the currents, as detailed in my paper read on December 22,1887 [see PP/11/14], required to fuse different wires of such thicknesses that the law C = ad3/2 is strictly followed; and I submit the following as the final values of the constant “a” for the different metals'. Annotations in pencil and ink. Subject: Electricity Received 15 March 1888. Read 19 April 1888. A version of this paper was published in volume 44 of the Proceedings of the Royal Society as 'On the heating effects of electric currents. No. III'. 1888