rays, that an aperture not larger than the pupil of an eye, wherever it be placed within the hemisphere, shall be fure to receive fome of them. What floods of light are continually poured from the fun we cannot eftimate; but the immenfity of the sphere which is filled with its particles, even if it reached no further than the orbit of the earth, we can in fome fort compute: and we have reafon to believe, that, throughout this whole region, the particles of light lie, in latitude at leaft, near to one another. The fpiffitude of the fun's rays at the earth is fuch, that the number which falls upon a burning glafs of an inch diameter, is fufficient, when concentrated, to fet wood on fire.

The tenuity and the velocity of particles of light, as afcertained by feparate obfervations, may be faid to be proportioned to each other: both furpaffing our utmoft ftretch of compr henfion; but proportioned. And it is this proportion alone, which converts a tremendous element into a welcome vifitor.

It has been obferved to me by a learned friend, as having often ft uck his mind, that, if light had been made by a common artist, it would have been of one uniform colour:

whereas, by its present compofition, we have that variety of colours, which is of fuch infi nite ufe to us for the diftinguishing of objects; which adds fo much to the beauty of the earth, and augments the ftock of our innocent pleas fures.

With which may be joined another reflec tion, viz. that, confidering light as compounded of rays of feven different colours, (of which there can be no doubt, because it can be refolved into thefe rays by fimply paffing it through a prifm,) the conftituent parts must be well mixed and blended together, to produce a fluid, fo clear and colourlefs, as a beam of light is, when received from the fun,

CHAP

CHAPTER XXII.

ASTRONOMY.

My opinion of Aftronomy has always been, that it is not the beft medium through which to prove the agency of an intelligent Creator; but that, this being proved, it fhews, beyond all other sciences, the magnificence of his operations. The mind which is once convinced, it raises to fublimer views of the Deity, than any other fubject affords; but is not fo well adapted, as fome other fubjects are, to the purpose of argument. We are deftitute of the means of examining the conftitution of the heavenly bodies. The very fimplicity of their appearance is against them. We fee nothing, but bright points, luminous circles, or the phafes of fpheres reflecting the light which

*For the articles in this chapter marked with an afterisk, I am indebted to some obliging communications, received (through the hands of the Lord Bishop of Elphin) from the Rev. J. Brinkley, M. A Andrew's Profelor of Aftronomy in the University of Dublin.

falls

falls upon them. Now we deduce defign from relation, aptitude, and correspondence of parts. Some degree therefore of complexity is neceffary to render a fubject fit for this fpecies of arguBut the heavenly bodies do not, ex

ment.

cept perhaps in the inftance of Saturn's ring, prefent themselves to our obfervation as com pounded of parts at all. This, which may be a perfection in them, is a difadvantage to us, as enquirers after their nature, They do not come within our mechanics.

And what we fay of their forms, is true of their motions. Their motions are carried on without any fenfible intermediate apparatus: whereby we are cut off from one principal ground of argumentation and analogy. We have nothing wherewith to compare them; no invention, no discovery, no operation or refource of art, which, in this refpect, refembles them. Even thofe things which are made to imitate and reprefent them, fuch as orreries, planetaria, cœleftial globes, &c. bear no affinity to them, in the cause and principle by which their motions are actuated. I can affign for this dif ference a reason of utility, viz. a reason why, though the action of terreftrial bodies upon each other be, in almost all cafes, through

the

the intervention of folid or fluid fubftances, yet central attraction does not operate in this manner. It was neceffary that the intervals. between the planetary orbs fhould be devoid, of any inert matter either fluid or flid, becaufe fuch an intervening fubftance would, by its refiftance, deftroy those very motions, which attraction is employed to preferve. This may be a final caufe of the difference; but ftill the difference deftroys the analogy.

Cur ignorance, moreover, of the fenfitive natures, by which other planets are inhabited, neceffarily keeps from us the knowledge of numberk fs útilities, relations, and fubferviencies, which we perceive upon our own globe.

After all; the real fubject of admiration is, that we understand so much of aftronomy as we do. That an animal confined to the furface of one of the planets; bearing a lefs proportion to it, than the fmalleft microscopic infect does to the plant it lives upon; that this little, bufy, inquifitive creature, by the use of fenfes which were given to it for its domeftic neceffities, and by means of the affistance of thofe fenfes which it has had the art to procure, fhould have been enabled to obferve the whole fyftem of worlds to which itown belongs;

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