Dr. Herschel’s additional Observations , &c. 355 
have, in my first Paper, sufficiently noticed the want of a proper 
criterion for ascertaining the temperature of the early periods 
where the sun has been recorded to have been without spots, 
and have also referred to future observations for shewing 
whether a due distribution of dry and wet weather, with other 
circumstances which are known to favour the vegetation of 
corn, do or do not require a certain regular emission of the solar 
beams, yet, I might still have added, that the actual object we 
have in view, is perfectly independent of the result of any ob- 
servations that may hereafter be made, on the favourable or de- 
fective vegetation of grain in this or in any other climate. For, 
if the thermometer, which will be our future criterion, should 
establish the symptoms we have assigned, of a defective or co- 
pious emission of the solar rays, or even help us to fix on diffe- 
rent ones, as more likely to point out the end we have in view, we 
may leave it entirely to others, to determine the use to which a 
fore-knowledge of the probable temperature of an approaching 
summer, or winter, or perhaps of both, may be applied ; but still 
it may be hoped that some advantage may be derived, even in 
agricultural economy, from an improved knowledge of the na- 
ture of the sun, and of the causes, or symptoms, of its emitting 
light and heat more or less copiously. 
Before I proceed, I must hint to those who may be willing to 
attend to this subject, that I have a strong suspicion that one 
half of our sun is less favourable to a copious emission of rays 
than the other ; and that its variable lustre may possibly appear 
to other solar systems, as irregular periodical stars are seen by 
us ; but, whether this arises from some permanent construction 
of the solar surface, or is merely an accidental circumstance, 
Z z 2 
