596 rHILOSOPHICAL TRANSACTIONS. [aNNO 1742. 



beginning and end of winter. Almost every full and change of the moon 

 very hard gales from the north. The constant trade-winds in these northern 

 parts he thinks undoubtedly to proceed from the same principle, which Dr. 

 Halley conceives to be the cause of the trade-winds near the equator, and their 

 variations. For that the cold dense air, by reason of its great gravity, conti- 

 nually presses from the polar parts towards the equator, where the air is more 

 rarefied, to preserve an equilibrium or balance of the atmosphere, is very evi- 

 dent from the wind in those frozen regions blowing from the north and north- 

 west, from the beginning of October till May ; for when the sun, at the be- 

 ginning of June, has warmed those countries to the northward, then the south- 

 east, east and variable winds, continue till October again ; and doubtless the 

 trade-winds and hard gales may be found in the southern polar parts to blow 

 towards the equator, when the sun is in the northern signs, from the same 

 principle. 



The limit of these winds from the polar parts, towards the equator, is seldom 

 known to reach beyond the 30th degree of latitude; and the nearer they ap- 

 proach to that limit, the shorter is the continuance of those winds. In New 

 England it blows from the north near 4 months in the winter; at Canada, about 

 5 months ; at the Dane's settlement in Davis's Straits, in the 63d degree of 

 latitude, near 7 months; on the coast of Norway, in 64°, not above 5^. 

 months, because blowing over a great part of the ocean, as before-mentioned; 

 for those northerly winds continue a longer or shorter time, as the air is more 

 or less rarefied, which may very probably be altered several degrees, by the na- 

 ture of the soil, and the situation of the adjoining contments. 



The vast bodies of ice met with in the passage from England to Hudson's- 

 bay, are very surprising, not only as to quantity, but magnitude, and as unac- 

 countable how they are formed of so great a bulk, some of them being im- 

 mersed JOO fathom or more under the surface of the ocean; and a 5th or 6th 

 part above, and 3 or 4 miles in circumference. Some hundreds of these are 

 sometimes seen in a voyage, all in sight at once, when the weather is clear. 

 Some of them are frequently seen on the coasts and banks of Newfoundland 

 and New England, though much diminished. When becalmed in Hudson's- 

 straits for 3 or 4 tides together, Capt. M. has taken a boat, and laid close to 

 the side of one of them, sounded, and found 100 fathom water all round it. 

 The tide flows here above 4 fathom ; and he has observed, by marks on a body 

 of ice, the tide to rise and fall that difference, which was a certainty of its being 

 aground. And in a harbour in the island of Resolution, where he continued 

 4 days, 3 of these isles of ice came aground. He sounded along by the side 



