Optics-^Meteorology. 3^ 



green colour and slimy appearance by day, so that it might have beeii 

 mistaken for the green vegetable matter common on stagnant pools. We 

 have taken up a quantity of this green- coloured water, and by keeping it 

 till night, have ascertained that the green colour by day, and the phosphores- 

 cent appearance by night, were occasioned by the same substance. ' 

 The causes of this luminous appearance in the sea are doubtless various 

 in different parts of the ocean. We know that fish, when dead, afford si- 

 milar light, and experiments have shown that dead fish immersed in sea 

 water, after a time, afford it also. The spawn of fishes is said to afibrd it, 

 and putrefaction is considered as a very common cause of this appearance. 

 In the present instance it appeared unequivocally to proceed from innumer- 

 able granular gelatinous bodies, about the size of a pin's head. These, when 

 taken upon the hand, moved about with great agility for a second or two, 

 when they ceased to be luminous and remained immoveable. — Finlaysons 

 Account of Siam, 



8. Magnificent achromatic Telescope executed in Paris.-— "SVe have late- 

 ly been informed by one of our scientific countrymen now in Paris, that 

 M. Lerebours, an eminent French optician, has executed an achromatic tele*' 

 scope with an aperture of twenty -four inches, and a focal length of twenty-' 

 five feet. The object glass is made of M. Guinand's glass. The telescope 

 cost 4-0,000 francs (about L. 1670,) and the stand about 10,000 francs 

 (L. 415) making in all about L. 2080. It has been now above three 

 months in the Observatory, but no good opportunities for observing with 

 it have occurred. Whether this grand instrument turn out well or ill, its 

 execution does honour to the spirit and genius of the French nation, and 

 to the monarch in whose reign it has been made. 



METEOROLOGY. 



9i Red Main, supposed to arise from Butterflies. — The following nar- 

 rative seems curious and important in connection with the various accounts 

 of red rain. It is extracted from Gassendi's Life of Peiresc, p. 110-113. 

 *' Through the whole of this year (1608) nothing gave M. Peiresc great- 

 * er pleasure than his observations upon the bloody rain, said to have fallen 

 about the beginning of July. Large drops were seen both in Paris itself 

 upon the walls of the cemetery of the greater church, which is near the 

 walls of the city, upon the walls of the city, and likewise upon the walls 

 of villas, hamlets, and towns for some miles round the city. In the first 

 place, M. Peiresc went to examine the drops themselves, with which the 

 stones were reddened, and spared no pains to obtain the means of convers- 

 ing with some husbandmen beyond Lambesc, who were reported to have 

 been so astonished at the shower, as to leave their labour and fly for safety 

 into the neighbouring houses. This story he ascertained to be without 

 foundation. To the explanation offered by the philosophers, who said 

 that the rain might have come from vapours, which had been raised out 

 of red! earth, he objected that evaporated fluids do not retain their former 

 hues, as is plainly exemplified in the colourless water distilled from red 

 roses. Nor was he bett* satisfied with the opinion of the vulgar, counte- 

 nanced by some of the theologians, who maintained that the appearance 



