316 Intelligence and Miscellaneous Articles. 
favoured by the proportionality of the strength of the current to the 
intensity of light. This resulted approximately from the experi- 
ments collated in the following table :— 
Intensity of light in } . , : 
standard candles ... } 6-4 99 | 12:8 | 168 
Strength of current ..| 18 30 40 48 
Quotient “4.ssscccree 28 3 371 2°8 
The luminosity was determined by means of a Bunsen’s photo- 
meter, and the strength of the current was determined by the 
deflection of a delicate reflecting-galvanometer. 
When the gold-leaf was exposed to illumination from the south- 
east side of the unclouded sky, while the sun itself was hidden by 
adjacent high buildings, the measurements given in the following 
table were obtained. 
h mihm Boe hm /hm; hm /hm{jhm/hm\thm{hm 
Time of ob- 9 37/10 510 30.11 0,11 35) 12 |12 30/1 O}1 20/2 0/2 30:3 0 
servation... 
Deflection 
of the 1901196; 209 | 223] 250 |250] 244 | 245 | 249 | 228) 188 | 173 
galvanometer. 
Mirite eee. 3'30| 4 
Deflection ...} 172/108 
It follows from this that the electromotive force of the selenium 
plate increased pretty regularly from the morning at 9.30 to mid- 
day at 11.35, and then remained constant with some variations, 
after which it decreased pretty regularly to 3 o’clock. 
Mr. Fritts is unable to offer any explenation as to the reason 
why some plates become better conductors, and some act as elec= 
tromotors ; he complains of the uncertainty in the preparation of 
the selenium plates, the properties of which cannot be foreseen, 
and he gives various methods of dealing with them, by which 
plates which are often inactive maybe used. More thorough investi- 
gations will therefore be necessary to establish what is due to the 
electromotive action of ight on many selenium plates. Neverthe- 
less the existence of a single selenium plate with the properties 
described is a fact of the greatest scientific importance, for here we 
meet for the first time with an instance of the direct conversion 
of the energy of light into electrical energy.—Sitzungsberichte der 
Akad. der Wissen. zu Berlin, Feb. 12, 1885. 
