1886.] On the Sun-spot Spectra Observations at Kensington. 347 



W. H. Preece, Esq., F.R.S. (see " The Effects of Temperature on 

 the Electromotive Force and Resistance of Batteries," " Proc. Roy. 

 Soc," vol. 36, p. 48), states "that changes of temperalure do not 

 practically affect electromotive forces, hut that they materially affect 

 the internal resistance of cells." 



When the temperature of this element was lowered to about 145° F., 

 the reactions before mentioned took place. 



The tin taken up by the solution during heating commenced to 

 precipitate, increasing as the temperature lowered, and the metal fell 

 to the bottom of the cell in a form to be again utilised in the genera- 

 tion of the current. 



The amount of local action or chemical corrosion which took place 

 above 150° F. was excessive, but the metal taken up by the solution 

 was very much less when the temperature of the electrolyte was not 

 raised above the point of precipitation, 140° F. 



The metal taken up below this point appears to be precipitated 

 under the same conditions as that taken up at higher temperature, and 

 seems to be precipitated whether the circuit be open or closed. 



It will be seen on the curves F, G, H, I, J, with falling temperature 

 that the electromotive force increased between 150°|F. and 140° F., 

 this might have been due to the reactions which took place during the 

 precipitation of the metal. 



Further investigations to determine the efficiency of this element 

 would be of interest. 



V. "Further Discussion of the Sun-spot Spectra Observations 

 made at Kensington." By J. Norm AN Lockyer, F.R.S. 

 Commnnicated to the Royal Society by the Solar Physics 

 Committee. Received May 5, 1886. 



I have recently discussed, in a preliminary manner, the lines of 

 several of the chemical elements most widened in the 700 spots 

 observed at Kensington. 



The period of observation commences November, 1879, and extends 

 to August, 1885. It includes, therefore, the sun-spot curve from a 

 minimum to a maximum and some distance beyond. 



It is perhaps desirable that I should here state the way in which 

 the observations have been made. The work, which has been chiefly 

 done by Messrs. Lawrance and Greening, simply consists of a survey 

 of the two regions F — b and b — D. 



The most widened line in each region — not the widest line, but the 

 most widened, is first noted; its wave-length being given in the 

 observation books from Angstrom's map. Next, the lines which 



