224 I'HILOSOPHICAL TRANSACTIONS. [aNNO 1728. 



yet since, to answer tlie phasnomena of nature with regard to action and re- 

 action, the same force must necessarily be allowed to all quiescent bodies like- 

 wise; it could be of no effect. 



Astronomical Observations and Magnetical Fariations, made at Vera Cruz. 

 By Mr. Joseph Harris. Revised and communicated by Edm. Halley, F.R.S. 

 N°40], p. 388. 



The latitude of Vera Cruz, by several distant observations, made with a qua- 

 drant of 4 feet radius, Mr. Harris found to be 19° 12' n. 



March 11, 1727, o. s. there happened a considerable eclipse of the sun, 

 the greatest obscuration being about 104 digits ; and having that morning care- 

 fully adjusted the pendulum clock, and fixed a telescope to the index of the 

 foresaid quadrant, Mr. Harris observed it to begin in or about the s. e. by s. 

 part of the sun's disk, at 49-i- minutes afternoon, apparent time ; the altitude 

 of the sun's centre then was 67° 53'. 



The eclipse ended in or about the n. n. e. part of the solar disk, at 3"^ SQ^™ 

 p. M. at which time the sun's altitude was 28° 34'. 



In the years 1726 and 172/, Mr. Harris observed the magnetic variation 

 several times, and found it to be about 2-i- degrees easterly. He also observed 

 the variation several times on the voyage from England towards Vera Cruz, 

 but always found that the best observations, when compared together, differed 

 so much, that he could not depend on them, to much less than 3 or 4 degrees, 

 or sometimes half a point of the compass. 



A new Method for composing a Natural History of Meteors. By Mr. Isaac 

 Greenwood, Prof. Math, at Cambridge, Nezv England. N° 401, p. 39O. 



Mr. Greenwood here recoinmends it to all navigators to keep regular sea 

 journals of the weather, recording the winds, currents, variations, &c. and in 

 general all sorts of meteors whatever, that may be met with. 



This method in general is, that in addition to such observations as should be 

 made on land, there might be some account taken of those also that were made 

 at sea; which already are by far more numerous than what were ever made 

 ashore, or indeed what can be expected thence for some ages still to come. 



Some Observations towards composing a Natural History of Mines and Metals. 

 By Dr. Frank Nicholls, Prof. Anat. Oxon. N° 401, p. 402. 



Mines in general are veins or cavities within the earth, whose sides receding 

 from, or approaching nearer to eacli other, make them of unequal breadths in 



