62 PHILOSOPHICAI, TRANSACTIONS. [aNNO 1666. 



hours 56m. ; because that after the appearing of the spot, Jupiter had not con- 

 tinued long enough above the horizon to observe him with due distinctness. 

 But the night after, March 1st, at 7-|- hours in the evening, he saw this spot in 

 the middle of the belt, and at 5 hours 26m. in the morning, he saw it again 

 return precisely to the same place. 



An Account of some Boohs, lately published. N"" 10, p. 173. 



I. Hydrostatical Paradoxes, made out by New Experiments, for the most 

 part physical and easy, by the Honourable Robert Boyle. This treatise was 

 occasioned by the perusal of the learned M. Pascall's tract. Of the Equilibrium 

 of Liquors, and of the Weight of the Air. 



II. Nicolai Stenonis de Musculis et Glandulis Observationum specimen; cum 

 duabus Epistolis Anatomicis. 



III. Regneri de GraefF, de Succi Pancreatici Natura et usu^ Exercitatio Ana- 

 tomico medica. 



The accounts here given of these three books, being a description of the 

 contents, are omitted, as of no use at present. 



Observations and Directions concerning the Barometer. By Mr. Boyle » 



N' 11, p, 181. 



It will be requisite for observers with this instrument to give an account of the 

 situation of the place where the barometers stand ; because we may thus not 

 only be capable of judging whether the instruments were duly constructed, but 

 also because the observations may disagree, even when the atmosphere is in the 

 same state, as to weight, if one of them stand in a higher part of the country 

 than the other. For Mr. Boyle found, by comparing two barometers which 

 he had, the one at Oxford, the other at Stanton St. John's, that though the 

 former was a very good one, and the latter very carefully filled, yet because at 

 Stanton, which is the higher ground, the incumbent part of the atmosphere 

 must be lighter, than at Oxford, which is the lower place, there is generally 

 between 1 and 3 eighths of an inch difference. 



But as most barometrical observations are subject to exceptions, so he found 

 that to be the case with the preceding. For riding one evening from Oxford 

 to Stanton, and before he took horse looking on the barometer, he was sur- 

 prized to find at his coming to the latter place, which was at no great distance, 

 and also considering the shortness of the time, which was less than an hour and a 

 half, that the barometer at Stanton was short of its usual height from the other 



