646 PHILOSOPHICAL TRANSACTIONS. [aNNO 176g. 



great many trials with a very good compass, of Dr. Knight's construction, Mr. B. 

 found the variation to be 6 degrees west ; and by a dipping needle, he found, by 

 repeated trials, the dip of the north end of the needle to be 79 degrees. 



May 15, at 13''i p. m. apparent time, or l'' 7"" after high water, by a mean of 

 7 observations, he found the dip of the horizon of the sea, from the observatory, 

 to be 12' 18". Height of the barometer 29.70 inches; thermometer without, 

 24° ; thermometer within, 28°. And May 20, at 7'' :; p. m. apparent time, or 

 7*" 33"" after high water, from a mean of 8 observations, he found the dip = 

 12'25'''.5 ; barometer 29.70 inches ; thermometer without, 43°, and within 40°. 

 Both these observations were made on the n. n. e. point of the true compass. 

 Mr. B. found it was high water, at the full and change of the moon, at S*" 44™ 

 T, M. apparent time, at the Cape ; and, by a series of observations, he found the 

 water to rise 8 feet 1 inch, nearly, perpendicular at the spring tides ; and at neap 

 tides 6 feet 8 inches, perpendicular ; and the tides seemed to follow very regular, 

 as they ought to do when not disturbed by bad weather. June 8, he found the 

 height of the observatory 140 feet 6 inches above low water mark. 



XXXF^II. An Observation of the Transit of Venus, made at Isle Coudre near 

 Quebec. By Mr. T. Wright, Surveyor, p. 273. 



Having, June 1 and 2, made many obsei-vations of the sun's altitude, Mr. W. 

 found the clock too fast for mean time 2 1 "" 44 on June 1 , and 20™ 46'^ on 

 June 2; consequently the clock lost 574^ seconds in 24 hours. 



Saturday, June 3, the Morning cloudy, no Altitudes taken. 



At 2'' 49™ 22* by the clock, Mr. W. happened to take his eye off from the 

 very point where he afterwards found the external contact happened, imagining 

 he saw it something more to westward ; but, finding his mistake, he returned 

 to the former point, where he found Venus had made a very small impression 

 at 2'' 50™ 25 ». 



At 3*" 7™ 48' Venus appeared completely round to the eye, and to appearance 

 rather detached, and joined by a small dark thread or ligament, which prevented 

 the rays of light from appearing. 



At 3*^ 8™ 19' the rays of light just appeared, at the internal contact. 



The following contains the above times, as shown by the clock, reduced to 

 apparent time, by allowing a proportion of 57 seconds, its regular losing in 24 

 hours ; as appears by the preceding and the following corresponding altitudes. 

 Short — 2'' 49™ 22' — 17™ 32'=2'' 31™ 50' apparent time of the 1st observation. 



— 2 50 25 — 17 32 =2 32 53 apparent time of the 2d observation. 



— 3 7 48 — 17 31=2 50 17 ap. time of 1st obs. of internal contact. 



— 3 8 19 — 17 31 =2 50 48 ap. time of 2d obs. of internal contact. 

 The weather, at the time of the transit, was not clear enough to observe the 



