C 3 54 : 'J 
XVI. Additional Observations tending to investigate the Symptoms 
of the variable Emission of the Light and Heat of the Sun; 
with Trials to set aside darkening Glasses , by transmitting the 
Solar Rays through Liquids ; and a few Remarks to remove 
Objections that might be made against some of the Arguments 
contained in the former Paper. By William Herschel, LL. D 
F. R. S. 
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Read May 14, 1801. 
Having brought up the solar observations, relating to the 
symptoms of a copious emission of the light and heat of the 
sun, to the 2d of March, I give them continued in this Paper 
to the 3d of May. It will be seen, that my expectations of the 
continuance of the symptoms which I supposed favourable to 
such emissions, have hitherto been sufficiently verified ; and, by 
comparing the phenomena I have reported, with the corres- 
ponding mildness of the season, my arguments will receive a 
considerable support. 
I have given the following observations without delay, as 
containing an outline of the method we ought to pursue, in 
order to establish the principles which have been pointed out 
in my former Paper. But we need not in future be at a' loss 
how to come at the trilth of the current temperature of this 
climate, as the thermometrical observations, which are now 
regularly published in the Philosophical Transactions, can fur- 
nish us with a proper standard, with which the solar phasnomena 
may be compared. This leads me to remark, that, although I 
