310 PHILOSOPHICAL TRANSACTIONS. [aNNO I676. 



is an extraordinary alteration, as to temperature of the country, since the 

 Europeans began to settle there. Which change is generally attributed to the 

 cutting down of vast woods, with the clearing and cultivating of the country. 

 But that Ireland should also considerably alter without any such manifest cause 

 either invalidates that reason, or else evinces that quite different causes may 

 produce the same effect. For if it be true, as some compute, that this king- 

 dom was better inhabited and cultivated before the late civil wars, than at pre- 

 sent, viz. 1676, it should, according to the reasons alleged for the change 

 of temperature in America, be rather grown more intemperate, viz. for 

 want of cultivation : but the contrary is observable here, and almost every 

 one begins to take notice, that this country becomes every year more and 

 more temperate. Formerly it was not unusual to have frost and deep snows 

 of a fortnight or three weeks continuance; and that twice or thrice, some- 

 times oftner, in a winter; nay we have had great rivers and lakes frozen all 

 over ; whereas of late, especially these two or three years last past, we have 

 had scarcely any frost or snow at all. Neither can I impute this extraordinary 

 alteration to any fortuitous concourse of ordinary circumstances requisite to 

 the production of fair weather; because it is manifest, that it has proceeded 

 gradually, every year becoming more temperate than the preceding. Though 

 it be observed that frosty and snowy winters make early springs, and for 

 as little as we have had of either this winter, yet there has not within the 

 memory of any now living happened a forwarder spring in Ireland; since this 

 place could produce some store of ripe cherries in the midst of April. The 

 wind keeps for the most part here between the north-west and the south, 

 seldom at east, and yet less frequent at north or north-east, insomuch that many 

 here do not scruple to affirm, that for at least -^ of the year the wind is westerly; 

 and we have sometimes known passengers wait at Chester and Holyhead no less 

 than three months for a fair wind to come hither. 



The hygroscope I make use of, I thus contrived. I took two pieces of deal 

 board, though poplar would do better, each about two feet long, and a foot or 

 more in breadth, as AB, fig. 6, pi. Q. These being well planed and shotten, 

 that their edges might meet even together, in that position they were fastened 

 at each end between two ledges of oak, CC, of two inches broad ; fixing both 

 boards in, as pannels are set in wainscoat. This done, supposing ^ of an inch 

 to be the utmost distance that these two boards would shrink asunder in the 

 driest weather, I took a thin piece of brass, D, two or three inches long, and -^ 

 inch broad, and on one edge towards the end I measured 4- of an inch, dd, this 

 I divided into five equal parts, and with a small file made them into so many 

 fine teeth, like those of a watch- wheel. This piece of brass I placed flat, across 



