Solar Magnetic Period. 451 



apparently some action within the solar nucleus which is not 

 yet understood. For if the periods of direct and inverse tem- 

 peratures are collected in a table, marked D and I respectively, 

 it is seen that there is a peculiar sequence among them in rela- 

 tion to the sun spot curve. The D and I periods interchange 

 position in the table along with the sun spot variations, the I 

 type following the curve directly, and the D type inversely. 

 What this signifies in solar physics it is not yet possible to say, 

 though it probably has to do with the nature of so-called posi- 

 tive and negative magnetism. Such material needs perfecting 

 to reach its final form, but the clue here presented is so sug- 

 gestive that it is published as it stands at this time. 



Distribution of the Types D and I in a Sun Spot Period. Sun Spot 

 Period 1 2 3 4 5 6 7 8 9 10 11 12 13 14 



1878.. 



D 



I 



I 



I 



I 



D 



D 



I 



D 



D 



D 



I 



D 



D 



1879.. 



I 



I 



D 



I 



I 



I 



D 



I 



D 



D 



D 



D 



D 



D 



1880 .. 



D 



D 



D 



I 



I 



I 



I 



D 



I 



D 



D 



D 



I 





1881 .. 



D 



D 



I 



I 



I 



I 



D 



D 



D 



I 



I 



I 



D 



I 



1882.. 



D 



D 



D 



D 



D 



I 



I 



I 



I 



I 



I 



I 



I 



D 



1883 .. 



D 



D 



D 



D 



D 



I 



I 



I 



I 



D 



I 



I 



I 





1884.. 



D 



D 



D 



D 



D 



I 



I 



I 



I 



D 



D 



D 



D 



I 



1885.. 



D 



D 



D 



D 



D 



I 



I 



I 



I 



I 



I 



D 



D 



I 



1886 .. 



I 



D 



I 



D 



D 



I 



D 



D 



D 



D 



D 



I 



I 





1887 .. 



I 



I 



D 



I 



I 



I 



D 



I 



I 



D 



D 



D 



D 



I 



1888.. 



I 



I 



I 



I 



I 



I 



I 



D 



D 



D 



D 



D 



D 



I 



1889 .. 



I 



D 



I 



I 



D 



D 



D 



D 



D 



D 



I 



I 



I 





1890 .. 



I 



I 



D 



D 



I 



I 



I 



I 



D 



D 



D 



I 



D 



I 



1891 .. 



I 



I 



I 



I 



I 



D 



D 



D 



I 



I 



I 



I 



D 



D 



1892 .. 



D 



D 



I 



D 



D 



I 



I 



I 



I 



I 



I 



D 



I 



I 



1893.. 



D 



D 



I 



D 



I 



I 



D 



I 



I 



D 



D 



D 



I 





Temperatures direct D, inverted I. 



Art. LXII. Remarks on Colloidal Silver • by C. Barus. 



1. Lsr the absence of Dr. E. A. Schneider I wish to say that 

 there does not seem to be any real issue between the recent 

 note of Mr. Carey Lea* and our own work.f It was our 

 endeavor to arrive at new data relative to colloids in general, 

 and colloidal silver was chosen merely as a promising subject 

 for attack. "We showed at length that colloidal silver possesses 

 properties which can be explained with reference to the 

 analogous behavior of suspended sediments. Differences neces- 



* Carey Lea: this Journal: October, 1894. 



f Barus u. Schneider : Ostwald's Zeitschrif t : viii, p. 278, 1891 ; Wied. Annalen, 

 xlviii, p. 327, 1893. Full references to the above and other allied physical ques- 

 tions are there given. 



Am. Jour. Sci.— Third Series, Vol. XLVIII, No. 288.— Dec, 1894. 

 29 



