486 IHILOSOPHICAL TRANSACTIONS. [aNNO IJQS. 



If it hhould be objected, that such violent and unremitting decompositions 

 would exhaust the sun, we may recur again to our analogy, which will furnish 

 us with the following reflections. The extent of our own atmosphere we see is 

 still preserved, notwithstanding the copious decompositions of its fluids, in clouds 

 and falling rain ; in flashes of lightning, in meteors, and other luminous phe- 

 nomena; because there are fresh supplies of elastic vapours, continually ascend- 

 ing to make good the waste occasioned by those decompositions. But it may be 

 urged, that the case with the decomposition of the elastic fluids in the solar at- 

 mosphere would be very difi^erent, since light is emitted, and does not return to 

 the sun, as clouds do to the earth when they descend in showers of rain, To 

 which I answer, that in the decomposition of phosphoric fluids every other in- 

 gredient but light may also return to the body of the sun. And that the 

 emission of light must waste the sun, is not a difficulty that can be opposed to 

 our hypothesis. For as it is an evident fact that the sun does emit light, the 

 same objection, if it could be one, would equally militate against every other 

 assignable way to account for the phenomenon. 



There are also considerations that may lessen the pressure of this alledged diffi- 

 culty. We know the exceeding subtilty of light to be such, that in ages of time 

 its emanation from the sun cannot very sensibly lessen the size of this great 

 body. To this may be added, that very possibly there may also be ways of 

 restoration to compensate for what is lost by the emission of light; though the 

 manner in which this can be brought about should not appear to us. Many of 

 the operations of nature are carried on in her great laboratory, which we cannot 

 comprehend; but now and then we see some of the tools with which she is at 

 work. We need not wonder that their construction should be so singular as to 

 induce us to confess our ignorance of the method of employing them, but we 

 may rest assured that they are not a mere lusus naturae. I allude to the great 

 nurfiber of small telescopic comets that have been observed; and to the far 

 greater number still that are probably much too small for being noticed by our 

 most diligent searchers after them. Those 6, for instance, which my sister has 

 discovered, I can from examination afiirm had not the least appearance of anv 

 solid nucleus, and seemed to be mere collections of vapours condensed about a 

 centre. Five more, that I have also observed, were nearly of the same nature. 

 This throws a mystery over their destination, wiiich seems to place them in the 

 allegorical view of tools, probably designed for some salutary purposes to be 

 wrought by them ; and, whether the restoration of what is lost to the sun by the 

 emission of light, the possibility of which we have been mentioning above, may 

 not be one of these purposes, I shall not presume to determine. The motion 

 of the comet discovered by Mr. Messier in June, 1770, plainly indicated how 

 much its orbit was liable to be changed, by the perturbations of the planets; 



