282 PHILOSOPHICAL TRANSACTIONS. [aNNO 1793. 



expansion instrument. Indeed, on the least reflection it must be obvious to 

 every one, that the changes of temperature of the fluid in a ball of 14- inch dia- 

 meter, cannot be expected to be so quick as in one of 0.22 of an inch. It is 

 also of the utmost consequence in making experiments with this instrument, 

 though it will render it extremely tiresome to the experimenter, that it be in 

 continual motion; for should tloat precaution not be observed, very considerable 

 errors indeed will take place. 



END op THE EIGHTY -SECOND VOLUME OP THE ORIGINAL. 



/. Of tivo Rainbows, seen at the same Time, at Alverstoke, Hants, July 9, 

 1792. By the Rev. Mr. Sturges. Anno \7Q3, Fol. LXXXIII. p. 1. 



On the evening of July 9, 1792, between 7 and 8 o'clock, at Alverstoke, 

 near Gosport, on the sea coast of Hampshire, there came up, in the south-east, 

 a cloud with a thunder- shower; while the sun shone bright, low in the horizon 

 to the north-west. In this shower 2 primary rainbows appeared, not concentric, 

 but touching each other, in the south part of the horizon; with a secondary 

 bow to each, which also touched each other. Both the primary bows were very 

 vivid for a considerable time, and at different times nearly equally so; but the 

 most permanent one was a larger segment of a circle, and at last, after the other 

 had vanished, became almost a semicircle; the sun being near setting. It was a 

 perfect calm, and the sea was as smooth as glass. 



If I might venture to offer a solution of this appearance, says Mr. Sturges, it 

 would be as follows. I consider the latter bow as the true one, produced by the 

 sun itself; and the other as produced by the reflection of the sun from the sea, 

 which, in its perfectly smooth state, acted as a speculum. The direction of the 

 sea, between the Isle of Wight and the land, was to the north-west, in a line 

 with the sun, as it was then situated. The image reflected from the water, 

 having its rays issuing from a point lower than the real sun, and in a line coming 

 from beneath the horizon, would consequently form a bow higher than the true 

 one. And the shores, by which that narrow part of the sea is bounded, would, 

 before the sun's actual setting, intercept its rays from the surface of the water, 

 and cause the bow, which I suppose to be produced by the reflection, to disappear 

 before the other. 



//. Description of the Double-Horned Rhinoceros of Sumatra. By Mr. tVm. 

 Bell, Surgeon at Bencoolen. p. 3. 



This animal was shot with a leaden ball from a musket, about 10 miles from 

 Fort Marlborough. Mr. B. saw it the day after; it was then not in the least 



