220 Prof. B. Stewart and Mr. W. L. Carpenter. [Feb. 25, 



Fig. 2 is a sketch of the low-resistance combination, showing the 

 hole into which the Thomson cell is inserted. 



Fig. 3 shows the portable arrangement to prevent fracture of the 

 silk suspension. 



February 25, 1886. 



Professor STOKES, D.C.L., President, in the Chair. 



The Presents received were laid on the table, and thanks ordered 

 for them. 



The following Papers were read : — 



I. " On a Comparison between Apparent Inequalities of Short 

 Period in Sun-spot Areas and in Diurnal Declination-ranges 

 at Toronto and at Prague. By Balfour Stewart, M.A., 

 LL.D., F.R.S., and William Lant Carpenter, B.A., B.Sc. 

 Received February 17. Read February 25, 1886. 



1. In a report fco the Solar Physics Committee (" Proc. Roy. Soc," 

 vol. 37, p. 290, 1884) we discussed the relations between certain 

 apparent Inequalities of short periods in sun-spot areas on the one 

 hand and diurnal temperature-ranges at Toronto and at Kew of cor- 

 responding periods on the other. 



In the present communication we proceed to discuss the connexion 

 between the same solar Inequalities and the diurnal declination-ranges 

 at Toronto and at Prague. 



For the Toronto declination-ranges we are indebted to the kindness 

 of the Science and Art Department, South Kensington, and of Mr. 

 Carpmael, Director of the Toronto Observatory, through whom we 

 have received daily values (excluding Sundays) of the diurnal range of 

 magnetic declination at Toronto extending from 1856 to 1879 inclu- 

 sive, and thus forming a series of 24 years. 



Each number is the difference in scale-divisions of the declinometer 

 between the greatest eastern and the greatest western deflection of 

 the declination magnet on each day, as observed at the hours 6 a.m., 

 8 A.M., 2 p.m., 4 p.m., 10 p.m., and midnight of Toronto mean time, one 

 scale-division of the instrument being equal to 0'*72 nearly. It is 

 probable that such differences represent very nearly the true diurnal 

 range. 



Disturbances appear to be violent at Toronto, and we have rejected 



