734 
Longevity 
[November, 
great, as may be seen by observing its illumination of dis- 
tant objects. The Bessemer shop at Sir John Brown and 
Co.’s Works, Sheffield, had window-openings at the sides 
and roof ; and standing on Grimesthorpe Hill, half a mile 
away, I have frequently, on misty nights, seen beams of 
light pouring through these openings, and stretching to the 
low clouds, on which the image of the opening was projected 
as on a screen. In all weathers the night illumination of 
these windows by the carbonic oxide flame was magnificent. 
It appears to me that this subject is of great philosophical 
interest. If the sun has a temperature approaching that 
assigned to it by Prof. Langley and others, all hopes of 
studying solar physics by comparison with terrestrial pheno- 
mena are at an end. The revelations of the spectroscope 
must be but snares and delusions, since the activities of 
gaseous molecules or atoms incandescent at such temper- 
atures should set their wave-lengths and refrangibilities at 
such variance with those in our laboratories that we must 
either fail to recognise them or remodel our accepted theories 
of radiation. If, on the other hand, they have temperatures 
similar to those produced b} 7 the combinations of terrestrial 
elements, we may venture to accept the conclusions of the 
speCtroscopist concerning their identity, and reason upon 
possible effects of their dissociation and re-combination, our 
reasoning being then based on the only data we possess, 
viz., terrestrial experience. 
V. LONGEVITY, OR THE NATURAL DURATION 
OF LIFE. 
S HE subject of Dr. Richardson’s Opening Address at the 
Croydon Congress of the Sanitary Institute of Great 
Britain, recalls to our mind an admirable paper “ On 
the Longevity of Brain-Workers,” read at a Meeting of the 
American Public Health Association, in 1874, by Dr. George 
Beard, of New York.* Dr. Beard wished to prove the error 
of the accepted teachings in regard to the effeCt of mental 
labour. He therefore obtained statistics on the general 
* Quarterly Journal of Science, vol. v. (n.s.), p. 430. 
