Baron Lindeneau, who recently published a work on the diminution of the solar mass says, that the sun may have been imperceptibly subject to successive diminution since the science of astronomy has been cultivated. Baron Lindeneau supposes the sun's diameter to be 800,000 miles, 4,204,000,000 feet, or nearly 2000 seconds. We have not, he observes, hitherto possessed any instrument for measuring the diameter of the heavenly bodies to a second. The sun may therefore diminish 12,000 of its diameter, or 2,102,000 feet, without the possibility of being perceived. Supposing the sun to diminish daily two feet, it would require three thousand years to render the diminution of a second of its diameter visible.

Parhelia or Mock Suns

Account of those singular Appearances, called, Parhelia or Mock Suns.

As when two suns appear in th' azure sky,

Mounted in Phoebus' chariot fierie bright:

Both darting forth fair beams to each man's eye;

And both adorn'd with lamps of flaming light,

All that behold such strange prodigious sight,

Not knowing nature's work, nor what to weene,

Are wrapt with wonder, and with rare affrighte. Spenser.

A Parhelion is a meteor in form of a bright light, appearing on one side of the sun. Phenomena of this kind have been mentioned both by the ancients and moderns Aristotle observes, that in general they are seen only when the sun is near the horizon, though he takes notice of two that were seen in Bosphorus from morning till evening; and Pliny has related the times when such phenomena were observed at Rome. Gassendi says, that in 1635-1636 he often saw one mock sun. Two were observed by M. de la Hire in 1689; and the same number by Cassini in 1693; by Mr. Grey in 1700, and by Dr. Halley in 1702; but the most celebrated phenomena of this kind were seen at Rome by Scheiner; by Muschen-broek at Utrecht; and by Hevelius at Ledan. By the two former, four mock suns were observed; and by the latter, seven. Parhelia are apparently of the same size with the sun, though not always of the same brightness, nor even of the same shape; and when a number appear at once, there is some difference in both respects among them. Externally they are tinged with colours like the rainbow; and many have a long fiery tail opposite the sun, but paler towards the extremity. Parhelia are generally accompanied with coronas, some of which are tinged with rainbow colours, but others are white. (See Halo ) They differ in number and size; but all agree in breadth, which is that of the apparent diameter of the sun. A very large white circle, parallel to the horizon, generally passes through all the parhelia; and, if it were entire, it would go through the centre of the sun. Sometimes there are arcs of lesser circles concentric to this, touching: those coloured circles which surround the sun. They are also tinged with colours, and contain other parhelia. Other circles are said to have been obliquely situated with respect to all these. The order of the colours in these circles is the same as in the rainbow; but on the inside, with respect to the sun, they are red, as is also observed in many haloes. Parhelia have been visible for one, two, three, and four hours together; and in North America, they are said to continue some days, and to be visible from sunrise to sunset. When the parhelia disappear, it sometimes rains, or snow falls in the form of oblong spiculae, as Maraldi, Weidler, Krafft, and others, have observed; and because the air in North America abounds with such frozen spiculae, which are even visible to the eye, according to Ellis and Middleton, such particles have been thought to be the cause of all coronas and parhelia.

Mr. Wales says, that at Churchill, in Hudson's Bay, the rising of the sun is always preceded by two long streams of red light, one on each side, and about twenty degrees distant from him. These rise as the sun rises; and as they grow longer, they begin to bend towards each other, till they meet directly over the sun, just as he rises, forming there a parhelion, or mock sun. These two streams of light, he says, seem to have their source in two other parhelia, which riae with the true sun; and in winter, when the sun never rises above the haze or fog, which he says is constantly seen near the horizon, all these accompany him the whole day, and set with him. Once or twice he saw a fourth parhelion, directly under the sun; but this is not common. These facts being constant, are very valuable, and may throw great light on the theory of these remarkable phenomena. Sometimes parhelia appear in a different manner; as when three suns have been seen in the same vertical circle, well defined, and touching one another. The true sun was in the middle, and the lowest touched the horizon, and they set one after the other. This appearance was seen by Maleziew, in 1722. Other appearances similar to this are recited by Mr. Muschenbroek. Sometimes the sun has risen or set with a luminous tail projecting from him, of the same breadth with his diameter, and perpendicular to the horizon. Such an appearance was seen by Cassini in 1672 and 1692; by De la Hire in 1702; and by Mr. Ellis in Hudson's Bay. As M. Feuilee was walking on the banks of the river La Plata, he saw the sun rising over the river, with a luminous tail projecting downwards, which continued till he was six degrees high. Paraselae, or mock moons, have also been, seen, accompanied with tails and coloured circles, like those which accompany the parhelia. An account of several, and a particular description of a fine appearance of this kind, may be seen in Muschenbroek.

The following account of this phenomenon is extracted from a pamphlet, entitled, ' Somewhat written by occasion of Three Sunnes' seene, at Tregorie, in Cornwall, the 22nd of December last; with other memorable occurrents in other places, imprinted 1622: 20 pages small 4to.'

"Since this strange apparition, namely, upon the 10th of January last, there happened in Devonshire, yet not farre from the other place, being on the edge of Cornwalle, another wonder, which, did as much affrighte the eares of men, as this did their eyes: for in the afternoone of that day, being the Thursday after Twelfth-day, there were heard in the aire un-usuall cracks or claps of thunder, resembling in all points the sound of many drums together, sometimes beating charges, sometimes retreats, sometimes marches, and all other points of warre: which, after it had continued a good time, it seemed that the same thunder did most lively expresse many volleyes of small-shot, and afterwards the like volleyes of ordnance, with so great and yet so distinct noyse, that many of them who dwelt neare the sea, went toward the shore to see what it might meane, as verily supposing there had beene some sea fight neere upon that coast. These severall fearful! noyses were againe and againe renewed in the same order, till at length with an horrible and extraordinary cracke of thunder, there fell in a ground of one Robert Pierce, where there were divers workemen planting apple-trees, (which ground lay neere the house of one Master George Chidley,) a thunder-bolt, if I may so call it, being a stone of three foot and an halfe in length, of two foot and an halfe in breadth, and one foot and an halfe in thicknesse, the substance whereof was in hardnesse and colour not much unlike a flint, as appeares by many pieces thereof, which are showed up and downe by many credible and honest gentlemen, who, with their own hands, brake them off from the maine stone. After the fall of this stone, which with the weight thereof was cleane buried in the ground above a yard deepe, the thunder ceased, and people began as much to won-at that which they now saw, as they had lately done at that, which with so much feare and amazement they had heard."