YOL. LXI.] FHILOSOPHICAL TRANSACTIONS. ' QS 



///. Observation of the Transit of Mercury over the Sun, Nov. Q, I769. By 

 J. tVinthrop, Esq., F. R. S., Cambridge, New England, p. 5 1 . 

 On Thursday the gth of November, Mr. W. had an opportunity of observing 

 the transit of Mercury. He had carefully adjusted his clock to the apparent 

 time, hy correspondent altitudes of the sun, taken with the quadrant for several 

 days before, and with the same reflecting telescope as he nsed for the transit of 

 Venus. He first perceived the little planet making an impression on the sun's 

 limb at 2''52'"41'; and it appeared wholly within at 53"" 58' apparent time. 

 The sun set before the planet reached the middle of its course; and for a con- 

 siderable time before sun-set, it was so cloudy, that the planet could not be dis- 

 cerned. So that he made no observations of consequence except that of the 

 beginning, at which time the siin was perfectly clear. This transit completes 

 3 periods of 46 years, since the first observation of Gassendi at Paris, in l631. 



If^. Observations on the Heat of the Ground on Mount Vesv-vius. By JoJ^n 



Hotvard, Esq.,. F.R.S. p. 53. ,,,d ^^j.^..,, ^^^^,,1 jj^,^,, 



Mr. H. here communicates some observations which he made in June, on the 

 heat of the ground on mount Vesuvius, near Naples. On ascending the moun- 

 tain, he often immerged the bulb of a thermometer in the ground, but found 

 no sensible heat for some time? the first rising in the thermometer was 114°; 

 every 2 or 3 minutes, he observal the instrument, till he gained the summit. 

 At those times, he found it rising to \11°, 137°, 147° 164", and 172°: on the 

 top, in two places, in the interstices between the hard lava, it was 218". Such 

 a degree of heat, after he had overcome the inconvenience of the exhalations, 

 raised his curiosity to know if there was a still greater degree of heat in the 

 mouth of the mountain. Accordingly, he made a small descent, and, by 2 ob- 

 servations carefully and attentively made, the thermometer both times stood 

 at 240°. 



If it should be asked, how a person, either to their feet or in stooping or lying 

 down to make the observations, could endure such a degree of heat; Mr. H. 

 answers, that the heat, both at top and in the mouth of the mountain, was only 

 in particular places. This was known by the fumes; the hard masses of lava 

 were only warm, and even so tolerable as to permit him to lie on them, as he 

 was often obliged to do, when the thermometer was immerged, to make a true 

 observation. 



f^. Description of a Bird from the East Indies. By Mr. George Edivards, 



F.R.S. p. 55. 

 At Valentine House, near llford in Essex, the seat of Charles Raymond, Esq.; 

 Mr. E. saw some curious birds and other animals, from the East Indies; among 



