VOL. LVII.j 



PHILOSOPHICAL TRANSACTIONS. 



527 



^ VII, But as M. Pingre, in his tract on the sun's parallax, has some doubt 

 about the observations made at the Cape of Good Hoj)e, M. Planman has here 

 deduced the parallax from a comparison of the observations at Paris, and at Bo- 

 logna, with many of the other observations, as in this following table. 



Hence the medium of these means gives again 8".4Q for the sun's parallax. 

 But rejecting the 3d column, or that having the greatest deviation, the others 

 give for the solar parallax 8".30, differing very little from the former medium 

 8'''',28, deduced from the best observations. Hence then, from the late transit 

 of Venus, the sun's parallax may be stated at 8''.28, so far as the difference of 

 meridians can be depended on. And it apjDears to Mr. Planman that this quan- 

 tity, on more accurate observations from the next approaching transit of Venus, 

 will be found to be rather too much, than too little. 



XVJl. On the Manner of Inoculating the Small-pox, on the Coast of Barbary, 

 and at Bengal, from a Memoir, written in Dutch, by the Rev. Mr. Chais, at 

 the Hague. By M. Maty, M. D., S. R. S. p. 128. 



Having long thought that the Arabs, who, about the middle of the 6th cen- 

 tury, were the first who wrote on the small-pox, were likewise the first inventors 

 of the method to prevent the fatal consequences of that disorder, Mr. C. was 

 very desirous to get what information he could concerning the introduction of 

 inoculation in Africa, and in the East Indies. About 20 years before, Cassen 

 Aga, a Tripolitan ambassador at London, informed the people about him, that 

 inoculation was universally practised, as well at his court, as at Tunis and Algiers; 

 but that no certain account could be given, either of the introducers of the me- 

 thod, or of the place whence it took its rise. 



One of the chief ministers of state in Holland was so good, on this informa- 

 tion, and at Mr. C.'s desire, to send a few queries on that subject, drawn up 

 by himself, to a gentleman, who, for several years, had resided with a public 



