Thomas Jefferson Papers

Enclosure: Gabriel Crane’s Essay on Light as an Element, [ca. 5 January 1819]


Gabriel Crane’s Essay on Light as an Element

[ca. 5 Jan. 1819]

An exposition of the Element of Light

The principal properties of this Element are light and Heat—the former is probably constituted by a superior brightness similar to polished metal united with transparency and the peculiar color of the Element—where ever there is light this Element is with its particles in connection.1 This position results from the long established fact that there is no other source of light or medium of sight and from the axiom that matter cannot operate beyond itself nor one Species or kind communicate its characteristic properties to another—That a connection of the particles is necessary to the display of this property it is reasonable to infer from the observation that the greatest accumulations of it in its diffused or disconnected State does not afford any light—There is obviously a much greater quantity of this Element in the atmosphere when the Sun is absent in the Summer Season than in the winter when it is preasent as is demonstrated by the heat Yet in the former there is comparitively extremely little light—which circumstance it is most reasonable to suppose2 results from its disconnection—That the rays of the Sun in the winter Season are3 sparse as to afford less heat than the quantity of that Element that is in a state of diffusion at the surface of the Earth in the summer Yet the matter that composes them is so much more dense and in a state of connection or cohesion (for the diffused matter it is presumed must be in contact) as to unite the particles in illumination—The single particles and the points of their unity when merely in contact being too small to operate upon our sight or to obviate in any degree the matters then excessive transparency—This Element passes through transparent substances in its state of cohesion the particles of those substances being globular have vacant space between them which with their fineness constitutes transparency. These positions result from the necessity of the Element of light,s being in that state to display its luminous property and the axiom that two particles of matter cannot occupy one point of space at the same time.4 It is reflected by the turning of its rays without destroying its force or continuity and is connected with the intellectual seat of vision in man and the animals by the organs of sight,s being composed of transparent matter.

Heat is a pungent property of this Element and is correspondent to its quantity density and motion—the latter forces it into greater and closer contact with other substances against which it strikes and also increases the cooperation of its own particles by the pressure—Being immersed in this Element as in a flood if we rub two pieces of wood together it is forced into them by the motion and pressure untill the collection is sufficient and sufficiently dense to create a concentration when it assumes its state of illumination by a sudden addition of matter that is occasioned by the commencement of that operation—thus fire is produced by friction—Its production by the flint and steel is upon the same principle but is effected without the concentration—the violence of the operation and the peculiar adaption of the implements supply the comparative deficiency of matter (that is brot’ into cooperation) by the extraordinary compression—the peculiar adaption of the flint consists in its hardness the fineness of its texture and the form of its particles which is calculated to leave but very little and irregular space between them this constitution prevents the particles of the Element of light from being easily forced into it and they are consequently more compressed5 upon the surface where the fuel is simultaneously prepared by the seperation of small particles from the steel which is a combustible substance—

In the steel compactness hardness and combustibility are limited which constitutes its superior suitability for this operation.6 Fire is continued and increased by the accession of matter that is in its state of diffusion and is brot’ into contact with it7 by the concentration—the correctnes of8 this position is very obvious as instead of fire,s increasing when formed it would otherwise be immediately diffused by the emission. that it does emit and in proportion to the quantity that is in cooperation is demonstrated by the light and heat that is produced by it beyond the space that it occupies as we cannot be affected by Any matter without its comeing in contact with us. Flame is form’d and supported by the smoke which is composed of particles of the fuel that are carried off by the emission And the current of the concentration before they are perfectly calcined.

The cause of one substance being warmer than another is the difference of their textures by which the matter of heat passes less freely thro’ some than others and it is therefore most dense where it meets with the greatest obstructions which constitutes the warmer substances—the Element of light is so much finer than the matter that composes the finest wool or fur as to pass between its particles. This Element is attached to combustible matter by a species of attraction, a combination of it sufficient to corrode is necessary to its cohereing and that which is in a state of diffusion then incorporates with it as they come in contact and as the fuel is prepared by the partial operation of that which is previously in connection with it—this necessary preparation is retarded by water in the fuel or prevented if the quantity be comparatively too great by the restraint of the operation and excess of evaporation—the operation is also diversified by the diversity in the textures and qualities of the different kinds of fuel.

The concentration is occasioned by the rarefaction of the atmosphere which destroys its equilibrium and the denser air moves to the rarified or weaker part untill the equilibrium is restored carrying with it the Element of light that is mixed among it—Rarefaction is a distention of the atmosphere by an accumulation of the Element of light between its particles which seperates them and thereby diminishes its gravity and the Element of light haveing none to these Elements does not supply the deficiency that is occasioned by its operation—the determination of the Element of light to pass off from the Earth by the difference of its gravity to its own centre from that of the adjoining Ether likewise aids in the operation and contributes to the uniformity of the course of the diffuseing9 current. Gravitation is a property of matter by which the distinction of the Genera’s and the Unity of the Species that compose them are preserved. it does not operate between distinct genera’s—this is obvious from the Element of light,s passing off from the Earth which it could not do according to the law of gravitation if it operated between them—The Atmosphere Earth and Water are different species of matter10 composeing one genera The Element of Light and Ether comprise another The varieties of matter that compose the different substances of the Earth are kinds of one Species. If the Sun does emit the matter of light and Heat it must necessarily receive a corresponding supply—the obvious diffusion of that which composes its rays its continuance when the Sun is absent—Its fluctuations and the very great quantity of it that is maintaind at the surface of the Earth as is demonstrated by the great number of the artificial collections that are daily form,d and may be increased almost without restriction together with the corroborateing operation of those collections render the apparent continual emission of a great quantity of the matter from the Sun unquestionable. As the emission is supplied by a return of the same matter there must be as great a quantity of it at the extremity of the atmosphere in opposition to the Sun on its return to that body as we receive from it which matter must have assumed another state by which its relative gravity is increass’d and rendered Superior to the obstacles that oppose its opperation—the change in the modification of it must likewise have rendered it incapable of passing between the particles of the atmospheric Element—and it cannot displace them by its gravity (which operates upon the atmospheric Element in that situation by the latters being in the direction of its Centre) it being the least of the two—This Element as before observed passes off from the Earth by its being of less gravity than the adjoining Ether—it probably resumes and continues its direction from the Sun untill it comes to the region of Ether that is of the same gravity as itself where it is most reasonable to suppose it is prepared for its return to that body in a manner similar to the preperation of vapour for its return to the Earth or perhaps in precisely the same that is by collecting in the rarified regions of Ether and condensing and forming into small globules by its own weight and liquid property. Its bias to the direction from the Sun when it leaves the Earth probably contributes in some degree to the difference of temperature between the day and night by its passing off more rapidly and in a greater ratio in the latter than the former—The emission of this Element is probably caused by the Element of Ether as the former does that of water this may be inferred from the cause,s operateing on the Earth as well as at the Sun and consequently cannot be local. The Element of Ether is considered as before observ’d a species of the Same genera as the Element of light—and is attached to the Sun as the atmosphere is to the Earth. it extends the emissions of the Element of light by the ordinary operation of the gravitateing principle on fluids (that is preserving an equilibrium by maintaining an11 equality or regular gradation of the parts in density or gravity.) in conjunction with the velocity that is given to them by the operation of rarefying and seperateing them from the dense collections of the matter—this velocity is indicated by the emissions from the artificial collections of it upon the Earth extending in every direction from them to a very considerable distance almost instantaneously and in opposition to the current of the concentration—The Existance of the Element of Ether is intimated by the blue concave that is called the sky which must be composed of some kind of matter as void space would present no color—and the color that distinguishes it does not correspond to that of any other Element of which we have knowledge.

The temperature of the atmosphere is regulated very materially by its own constitution and construction—it thereby operates as the burning glass condensing the rays of the Element of light at the Surface of the Earth as at a focus that is formed by that implement—the Centre of a focus of the Element of light formed by the atmosphere or burning glass presents the greatest heat at the centre12 which diminishes gradually towards the exterior; the rays being more compact and haveing greater velocity progressively as they approximate to the Centre this systematic variation is occasioned by the progression in the degrees of their variation from the course in which they came in contact with the concentrator—the forceing of them from their original direction counteracts the operation of the concentrator and diminishes their velocity in a corresponding proportion to the angle of alteration whereby they become more sparse and have less force in a regular gradation from the Centre to the exterior of the focus—This position is corroborated by the following observations the simularity of the form and constitutions of the atmosphere and burning glass and the operation of the latter which demonstrate the variation and gradation of the heat of the focus likewise by the progressive diminution of heat in ascending Mountains the atmosphere being a fluid consequently preserves an even surface whereby the Elevation of Mountains diminishes its depth and density upon them comparative with the common levil of the Earth which occasions a corresponding sparsity of the rays of light by the focus being greater in proportion to the surface of the concentrator. this It is presumed is the most if not the only rational explication of the coldness of mountains that can be deduced from our knowledge there being no other difference of local circumstances between them and the common levil of the Earth that is calculated to affect the temperature than the one adduced—that the difference in the density of the atmosphere in those situations does not occasion the diversity of their temperatures is demonstrated by the same diversity, occurring at the general surface of the Earth where there is no material or permanent dissimularity in the density and is there occasioned by the movement of the focus of the Element of light13 and the difference in the degrees of the heat of its parts.

The twillight and that which is generally14 called Star light are produced by this operation of the atmosphere—The Sun being the larger body its rays consequently enter the atmosphere for more than half of its exterior extent and are sparsly conducted to the Earth the whole of the night—The Element of light as before observed does not afford the least degree of illumination in its diffused State which is frequently demonstrated by the collection of it in our Rooms And by the perfect darkness that ensues in the night when the rays are all interupted And destroyd by the quantity and density of the interposeing clouds—notwithstanding the diffused or disconnected matter does not afford any light Yet it enables us to See condensed15 collections of it much farther than their emissions extend and likewise to perceive the interveneing objects—It is by this latter circumstance that the light of night is apparently so equeally diffused and connected nowithstanding the great Sparsity of the rays.

The rays of the Element of light are extremely fine streams that are form’d by the Element of Ether which divides it as it extends and diffuses untill it becomes indivisible16 the cohesion of the particles that compose them is demonstrated and their astonishing flexibility by which they winde between the particles of other matter for a vast distance without haveing their continuity destroy’d strikeingly display’d in their reflection—The local variations of the temperature of the atmosphere are occasioned by the difference in the operations of the Element of light on earth and water and by its transmission in its state of diffusion by winds—In consequence of waters being transparent more of the rays of light penetrate into it than into the Earth and consequently the collection of that matter is greatest at the surface of the latter—difference of soil also causes a variation of temperature—those which are termed dry which admit water more speedily and to a greater depth into them than others present the greatest degree of heat on their surfaces which results from the penetration of the matter of heat into the Earth in proportion to the quantity of water that is mixed with it and from that matters receeding from dry soils with less vapour in connection with it than from wet as vapour diminishes its operation on other adjacent matter or bodies by obstructing the cooperation of its particles—As water when mixed with Earth occupies the space that would otherwise be vacant it might be inferr’d that such a mixture would present more obstruction to the Element of light than dry earth.17 It may therefore be necessary to observe that transparent matter presents smoothe surfaces that does not destroy the rays as those that are rough; they glance from the former and pass on when not prevented by deficiency of space—but the latter instantaneously destroys the greater part that comes in contact with it—the rays being so fine that the least protuberance on the surface of other matter is a direct and full obstruction and the forms of the particles of untransparent matter makes the incidental spaces between them irregular. the apparent roughness of transparent substances when broken does not affect this position it being occasioned by the unevenness of the general surface and not the roughness of the particles—The partial condensation of the Element of light in the atmosphere is occasioned by its connection with other substances by attraction as vapour and effluvia,s of most if not all the kinds of matter that compose the Element of Earth—which obstructs its diffusion by their gravity &c &c &c

The Comets are Spheres of the Element of light and are employ’d to contribute to the supply of the planets that are too far from the Sun to receive a sufficiency of that essential Element from its rays—Their orbits are prescribed by the following operation of the gravitateing principle—If an inferior body be propell’d from that to which it gravitates in a line that diverges from the centre of the latter it will return in a corresponding one so that a perpendicular from the zenith of its Asscension to the centre of gravity will divide its orbit into two equeal parts—Comets return towards the Sun by the operation of gravitation and recede from it by the continuation of the force that is acquired by that operation And by its own operation on the Element of Ether which is rarified by its rays and consequently as it moves in its orbit the denser Ether closes in behind it and constitutes a powerfull and Uniform impetus—the maximium of the Velocity of a Comet by gravitation takes place at the point of its orbit that is nearest to the sun which is in a line with the Centre of that body and the other extreme of its own orbit—its force by gravitation then precisely counterbalences its tendency to the centre of gravity and the other impetus constitutes a preponderance of power by which it resumes it course from the Sun—

The temperature of the planets being regulated by the Atmospheric Element as explaind in the exposition of the Element of light and in such a manner that an increase of it comparative to the size of the planet to which it is attached increases the temperature in a systematic proportion—and vice versa—Accordingly the atmospheres of the planets are adapted to their respective situations in the system and consequently those that are superintended by Comets have extremely large ones which receive from them a great quantity of the matter of heat and retain it in its State of diffusion—Those planets being such a great distance from the Sun that the gravitateing principle operates very feebly their on the Element of light and the Ether being very nearly of the same18 degree of gravity it is retaind by the attraction of the Elements that compose the planets.19 This attraction is the same that it is observd to have to our combustible and other matter at those planets it gives the Element of light a determination to their surfaces which occasions the wasteage in the abscence of the Comets to affect only the uper regions of the Atmosphere—Its concentrateing operation which eventuates in its greater20 diffusion preserves the desired temperature at the surface of the Earth (as with us) by preventing it from too great an Accumulation—The wasteage results from occasional extraordinary concurrences of successive concentrations that diffuse upwards and carry a portion of the Element of light so far from the Earth that its tendency to the region of Ether that corresponds with it in gravity becomes superior to its attraction and it consequently is thereby entirely extricated from the elements and influence of the planet the diminution is partially supplied in the abscence of the Comets by the rays of the Sun which likewise affords a sufficiency of light—

MS (MHi); written entirely in Crane’s hand on three numbered sheets, the first two folded to form four pages; undated.

1Omitted period at right margin editorially supplied.

2Preceding six words interlined in place of an illegible phrase.

3Word interlined in place of “tho’ so.”

4Omitted period at right margin editorially supplied.

5Manuscript: “compress.”

6Omitted period at right margin editorially supplied.

7Word interlined in place of “the dense collection.”

8Preceding three words interlined.

9Word interlined.

10Preceding two words interlined.

11Manuscript: “and.”

12Preceding three words interlined.

13Preceding four words interlined in place of “heat.”

14Manuscript: “generall.”

15Word interlined.

16Preceding twelve words interlined in place of an illegible phrase.

17Omitted period at right margin editorially supplied.

18Manuscript: “sam.”

19Omitted period at right margin editorially supplied.

20Word interlined.

Index Entries

  • astronomy; and comets search
  • astronomy; and light search
  • comets; properties of search
  • Crane, Gabriel; Essay on Light as an Element search
  • flint search
  • gravity; and light search
  • light; G. Crane’s essay on search
  • physics; light as an element search
  • steel; and fire search
  • sun; and atmospheric conditions search
  • sun; and comets search
  • weather; and earth’s atmosphere search