820 PHILOSOPHICAL TRANSACTIONS. [anNO 16S6- 



to be gone into, without spoiling it. Tliey iiave ruined the people of these 

 parts, who had no harvest the last year, and it will cost above 3000 livres to de- 

 stroy them this year. They have been taken in abundance in the neighbouring 

 villages. If this care had not been taken, there would have been enough of them 

 to have eaten up the corn of the whole province. 



yin Extract of two Essays in Political Arithmetic concerning the Comparative 

 Magnitudes, &c. of London and Paris. By Sir IVilliam Petty, Knt. R.S.S. 

 N° 183, p. 152. 



The author of these two essays has, in several former ones of the same na- 

 ture, made it appear that mathematical reasoning is not only applicable to lines 

 and numbers, but affords the best means of judging in all the concerns of 

 human life. In the present he endeavours to prove that London is the most 

 considerable city now in being, by showing it much to exceed Paris, both in 

 people, houses, and wealth. The first he proves by comparing the bills of 

 mortality, by which he finds that the people of London are as many as those of 

 Paris and Rouen put together. The second, by comparing the number of 

 houses, which by the chimney books are found above 80,000 in London, whereas 

 a great author among the French reckons but 50,000 houses in Paris. As to 

 the third, viz. the wealth, he conceives that there is yet a much greater dis- 

 proportion, there being no comparison between them for trade, &c. 



An Historical Account of the Trade Winds and Monsoons, observable in the Seas 

 between and near the Tropics ; with an Attempt to assign their Physical Cause. 

 ^,By E.Halley. N" 183, p. 163. 



The whole ocean may most properly be divided into three parts, viz. 1. The 

 Atlantic and Ethiopic Sea. 2. The Indian Ocean, 3. The great South Sea, 

 or the Pacific Ocean. And though these seas do all communicate by the 

 south, yet, as to our present purpose of the trade winds, they are sufficiently 

 separated by the interposition of great tracts of land, the first lying between 

 Africa and America ; the second between Africa and the Indian islands and New 

 Holland ; and the last, between the Philippine isles, China, Japan, and New 

 Holland, on the west, and the coast of America on the east. 



I. In the Atlantic and Ethiopic Seas, between the tropics, there is a general 

 easterly wind, all the year long, without any considerable variation, excepting 

 that it is subject to be deflected some few points of the compass towards the 

 north or south, according to the position of the place. The observations which 

 have been made of these deflections, are the following : 



