107

To the Editor of the Monthly Magazine..

SIR,

fact beyond the possibility of doubt, I looked by means of another prism at the light passing through, and perceived those fringes, as if hanging from the angles. Indeed, it is surprising, that these circumstances, so easily proved, so evident to the eye, and so highly important in their consequences, should have escaped the observation of such able and accurate

experimenters as those already menti oned. I shall conclude this paper with the following deductions.

1. That incident light has never yet been decomposed; and that Sir Isaac Newton and others only decomposed light reflected from opaque substances, or fringes of blue, red, and yellow.

2. That there are but three primary colours, blue, red, and yellow, by the mixture of which, in different states of Condensation, all the others are formed. 3. That Herschel, Leslie, Davy, Englefield, and other philosophers, drew their conclusions, relative to the heating power of the prismatic colours, from erro. neous data, viz. from experiments on refected light, whose heat must in a great measure depend on the reflecting media, and also on the thickness or thinness of the parts of the prism, through which the fringes pass; thus the red and yellow passing through the very thin angle, must be accompanied by more radiant caloric than the blue which rays pass through the thickest. But as I am at present engaged in a series of experiments to prove that the prismatic coloured rays have similar heating powers, I shall not here anticipate. The following diagram will demonstrate my opinions.

But in

endeavouring to ascertain what that distance is, these circumstances ought not to be omitted.

The Sun at 30 min. contains 1800 seconds.

At the Herschelian planet the angle is therefore about 1' 40", the distance being near 20 of ours; at 100 times it would be 20", and at 2000 times 1".-2000"120,000"

Were the Sun therefore removed to

120,000 times his present distance from

us in winter, he would still subtend an angle of 1". At twice that distance of 30, half a third.

At 3 times this distance, or $60,000 times his present distance, he would subtend an angle of only 20"".

And

There is no doubt that an object shining like our Sun, by inherent light, might be viMost therefore of the fixed stars which sible as a vivid point at this vast distance. are visible to the naked eye may be, and most probably are, thus distant. by a telescope stars may be discernible 100, 1000, even 10,000 times this dis tance, though by loss of light, they will not be seen so distinctly as if we were brought as much nearer to such stars as the power encreases the angle.

But 100,000,000X 560,000 x 10,000 $60,000,000,000,000,000-3616: =360 billions of miles.

It seems possible therefore that with our present means of observation we may see, and that Dr. Herschel and some few other astronomers have seen thus far of the Universal System: so that it is proba ble telescope stars are seen, the light of which has been 750 years in reaching ust. And if a diameter of any of the fixed stars of the 1st or 2d magnitude, for beyond it cannot be expected, could be measured with accuracy, we might judge what their distance must be by this scale; and at least discover what either that or their magnitude must be to subtend such an angle.

And it may be doubted whether such stars as Sirius, Capella, and Spica, and Regulus, Antares and Arcturus, Aquila and Lyra, are more than 240 or 250,000 times farther from us than our Sun.

But then on the other hand it will be

* Accurately, his present diam, is then (Jan. 1,) 32' 34" 16: as it is (June 1) 31a 34" 12.

+ It seems that Dr. Herschel has observed

objects vastly of more remote origin.

probable that almost all telescope stars are much more than 4 or even 500,000 times more remote. And indeed that stars of the 6th magnitude cannot be less than 360,000 times our distance. And stars of the 7, just discernible to the naked eye, not less than 600,000 times: so that the telescope stars nearest to us are probably 860,000 times as distant as the Sun from us; or 862,000,000,000,000 =8612, or 86 billions of miles. This will not appear enormous if it be considered that at 400,000 times our dis. tance stars even of the first magnitude have been generally considered to be; which would make them 39 bil. lions of miles distant: or nearly half the distance here conjectured for the nearest of the telescopic..

Mr. Pond's late observations as astronomer royal, by shewing that the parallactic angle, even of Aquila, if any, is nearly insenible, give an additional proof of the amazing distance of the fixed stars.

If Parker's burning lens has ever been applied to bring the rays of Sirius, when near the meridian, to a focus, and no sensible heat has been produced, this, I think, would prove that Sirius cannot be nearer than 300,000 times our distance. The squareof 300000 being 90000000000. Now, a mirror, or a lens, which should have a power of concentration as 30,000 would reduce this to 3006000 of the Sun's force here; which I apprehend might be sensible to a very delicate thermometer with a Nonius.

If a parallax in the fixed stars be ascertainable, perhaps it will be found in Sirius, Aldabaran, or Spica; if a sensible diameter, perhaps in Arcturus, or Foma haut. If a parallax of 6 had existed in Sirius, which would reduce his diameter to about of a second, and its distance to 78000 of the O, surely so considerable a parallax would ere now have been ascertained, and a disc so sensible could hardly have been altogether overlooked. CAPEL LOFFT. To the Editor of the Monthly Magazine. BIGNOR, a hamlet near the village of Bury, has lately become renowned as having produced some of the finest relics of art extant in this country, in a tessellated or Mosaic pavement. The circumstances attending its discovery are as follow: Mr. Tupper, the proprietor, a farmer, was, as usual, ploughing his fields after the harvest of 1811, when, in this field, which he himself has ploughed for the last thirty or forty years, the ploughshare received

a violent shock from a large stone. On examination it was found to be connected with others, so as to form the remains, of a wall, and on pursuing their researches, a fine pavement was discovered of various hues, and on which are depicted, first a majestic eagle with Ganymede, most exquisitely defined, with an eye that challenges superiority on canvas; also, a fine portrait of a female,

apparently intended for Juno, from her being attended by two birds nearest resembling peacocks, under which portrait are a number of small gladiators in the various attitudes of fighting.

The department from which the annexed portrait is taken had every appearance of having been an aisle, being forty-three feet in length, and about three in breadth, and contains a number of Grecian borders, sinall devices, and an insignificant dolphin, over which are the letters T. W. This is the first part to which the visitor is introduced. The second contains, besides the Ganymede, a Roman bath.

There are a number of other devices, and, it is thought, another figure, which is omitted to be described here, owing to the writer's having lost part of his remarks; but those which are described are the principal ones. The beauty of the situation, and its proximity to the old Roman road, being but five hundred yards distant, and which it exactly faces, induces a belief that it was a villa of one of the Roman generals. The road runs from Chichester, which was the headquarters of Vespasian, towards London, and Bury is about three miles from Arundel towards Petworth. S. LUKE.

To

about ten or eleven years, ascertained the positions of between 40,000 and 50,000 stars, from 0 to about 116° of N. Pol. dist. the catalogue of which was published in separate portions in the Connoisance des Temps, for the year 7, (1799) and subsequent volumes, nearly up to the present time.

2. Cit. Vidal, at Mirepoix, ascertained with great care and accuracy, the positions of 888 austral stars, for January 31, 1798. (I suppose this catalogue is in tended as a supplement to that of Lalande.)

3. M. Piozzi, astronomer at Palermo, in Sicily, published about 1800, or 1801, a general Catalogue of Stars; but whether a compilation, or an original work, I know not.

Quære the contents, arrangement, and peculiarities of these three Catalogues, of which the above short account is all I have been able to find.

If any of your correspondents should be in possession of, or have access to all, or any of the above Catalogues, an account of them, inserted in some future number of your Magazine, will be interesting.

Perhaps some of your correspondents may likewise be able to point out in what modern Catalogue the following stars of Bayer's are to be found. They form only a part of the characters omitted by Flamsteed, in his great work, which is far from containing ail the stars observed by preceding astronomers.

X Andromeda (52), 9, a And. (the Jatter of these is not in Fl. and I suspect the other two are not the same as in Bayer, Aurige-a Cassiopeia-w or b Cassi: (one of these two is not in Fl.) e Cygni (26) Eridani, (see Phil. Trans. lxxvi, 204, 205.)-g Geminorum (62), Gem. (6, 15, Cancri?)Herculis,-b Persei, (see Miss Herschel's Cat. No. 3 and 4.)-9,, x, gittarii,-y. E, 0, 0,, Scorpii, (20, 51, 40, 39, 48 Libre?)- Serpentis, (see Miss Herschel's Cat. No. 100,)-, π, Ophiuchi,- Oph. (66 Herculis?)

Sa

The following is a sketch of the number of stars observed by Flamsteed; his Bri. tannic Catalogue contains 2,935, of which 2,736 are completely observed; 64 imperfectly; 111* not observed at Besides all; and 24 inserted twice.

which, his observations contain 371 of the first class, and 132 of the second. Total, 3,107 completely, and 196 imperfectly observed.

ΑΣΤΡΟΦΙΛΟΣ,

Of these, the greater part do not exist,

To the Editor of the Monthly Magazine.

SIR,

EFLECTING on the original; as

R well as adopted principles: on the laying down; as well as the taking up doctrines, relative to life-equivalents and life-annuities, lately inserted in some of the numbers of your truly valuable repertory of science; they have not only, deeply instructed me; but also, highly entertained me.

Oh! that an apple, falling from a tree
Shou'd unfold the whole law of gravity!
That apple's fall, might be impell'd by chanco:
Consider'd a fortuitous event.

Nearer to Earth: the quicker in advance:
May lead to some future experiment;
Proving that Life's dependant premiums;
Solv'd by chance; are but chance deliriums.
Life though; an accelerative motion:
The older: the swifter, in proportion
Yet; being subject to fortuity:

As death retards its continuity.
This principle seems, a contradiction,
Nevertheless; it is not a fiction.

Two chords in music, both in size; not length: One, just half the other, tension'd fourfold,

Chimes in unison, to the other's strength:
Alike in concord: as the spheres of old.
This dupli-quadruple law of gamuts:
Reigns in harmony among the planets.
Planetary impulse is co-equal,

When distance is to distance, duplical:
And gravity quadruple, next the Sun,

Fair Science! that a falling apple won.
Great Newton's planetary monument,
This steel-yard principle does represent.
Orbs velocities, ellipsing the sun,

Ray-indexing amphiparabolas,
Or, two half orbits uniting in one:

In equal times: space equal areas.
Those planes are equal in astronomy:
Progressive too, in life-economy.
Planes, whether equable or augmented
Both, are interpreters of life-term laws :
Typicals of facts, thus represented;

But not affianc'd to those mental flaws:
Dissecting each person into fractions,
And adding reversions, by subtractions.
Some lemmatarian receptacles,

Premis'd for the mind, first to occupy:
Prove often; but hoodwinking-spectacles,
And such as strict truth cannot justify.
Thus purblinding-learned authority:
Keeps often plain-sense in minority.
The life-computing mathematicians,

Among their Lemmata, have this one to
know:

Being such excellent chance-tacticians, "Shoot at a pigeon; and strike dead, a crow,"

All questions with them; but count number

one:

So yield a result: as true, as their gun.

One