68 oJ. H. Lane on the Theoretical Temperature of the Sun. 
instead of the co-efficient 8377 we had used the larger co-effi- 
cient 12°808 which Hopkins gives for unpolished gprs ~ 
formula would have been reduced only 53° Cent. It best 
the direction of our inquiry to use the smallest co-efficient ich 
Hopkins’ experiments gave, since we are seeking the highest 
temperature which can be plausibly deduced from the sun’s 
shesatis may be valled the curve of radiation. The course of 
this curve from the freezing point of water to a point somewhat 
below the boiling point of mercury is correctly marked out to 
us by the formula. Beyond that we have but the rough 
approximation which we can get by means of the above com- 
parison, to the single point of the curve where the — : 
giath oat, of the sun’s photosphere. The attempt, from th 
data, to extend the curve till it reaches the full Siation 
of that photosphere, must be mainly conjectural As a 
basis for the most plausible conjecture I am able to make 
same temperature; secondly, that the curve of ster is 
conjectural assumptions—of the degree of probability of which 
€ greatest a 
ture the sun’s photosphere d have consistently with 
radiation of 64,000 at the temperature of 4000° Fah., is found =a 
drawing through the point representing that radiation and that 
temperature a straight line tangent to the curve of the formula. 
The line so drawn would cross the real curve of radiation in a 
greater or less angle at the radiation of 64,000 and tempera- 
ture of 4000° Fah., and at higher temperatures would fall mo ore 
or less below that curve, and its intersection with the sun’s 
radiation of 1,280,000 would be at a temperature greater than 
that 7 =~ curve, —_ = to say, greater than the tempera- 
ture of the sun’s osphere. This ter temperature is 
55,450° Fah. Fs te te 
‘A. different train of conjecture led me at first to assume 
