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fire yields light is an incontrovertible fact: it is also a truth,that there is light without heat or fire. Assuredly, the bestmode to settle this disputed point would be to distinguishlight into its various species : as light, self-existing, whichmust be presumed to be that kind of primitive light whichhad an existence anterior to the being of any luminousbody, and must have been the created light, of whichthe Hebrew historian speaks (purely elemental). Light,of the description of that described by Newton as issuingin particles or rays, from every part of some luminous body,may be properly termed solar light.: that kind producedby domestic or familiar objects; as light from candles,lamps, gas, &c. may be called domestic light; and thatspecies of light which jtroceeds from bodies without heat,as from the glow-worm, ignis faluus, phosphorus, putridfish, the Bologna stone, and carbuncle; all these bodiesbeing capable of emitting light in the dark, are surely sus-ceptible of a distinct name ; therefore, Newton’s idea maybe its distinguishing specific term; he calls it light ivitliaul, heat. That all the species of light, except the first wehave enumerated, have distinct causes for existence, someelementary, some dependent or consequent on other produc-tions ; likewise there is a fifth species of light, proceeding fromreflexion, but without heat; as that chaste light y ielded bythe moon, and in her absence by the stars, which is a stillmore weak and softened light. That they are also all sus-ceptible of distinction from their visible qualities, no lessthan for their original production, is a truth of which expe-rience convinces us. But the preceding five distinct speciesof light form one generic nature only; philosophy hashitherto bowed too much to vulgar habits to adopt its com-mon and confused idea, by expressing any and every de-scription of light by one vague and uncertain term only.
Although of all these species of light there is only oneof them entitled to the distinguishing appellation of anelement, which must be the first created existence. Andalthough a ray of solar light will pass through a vacuum,yet a domestic light will not burn in it, so essential to theexistence of this kind of light, is air.
To define the nature of light wall be, perhaps, infinitely• more difficult; this we think must be regulated by its severalspecific effects, being, perhaps, as various as their objectsare dissimilar. However, from what has preceded, someidea may be collected upon this head for its illustration. .
Of every property of light, none is so truly astonishing