VOL. XI.J PHILOSOPHICAL TRANSACTIONS. 34f 



distance left in the middle for the scope of the motion. — C, the hand fastened 

 by the axletree to the plate, and also with nail-holes which are to fasten it to 

 the middle of the pannel, within half an inch of the scope for motion ; at the 

 lower or shorter end of the axletree there is fastened, by a wire like an S, a 

 small silver chain within a straw's breadth of the axletree; which chain is to be 

 carried and placed across the distance between the two pannels, and fastened to 

 the opposite pannel by a brass noose, through which it is to slip, so as to be 

 taken up or let down at pleasure. — D, the roller, with a weight annexed, which 

 by a string is fastened to the lower end of the hand C ; so that, as it relaxes and 

 gives way, the weight will adjust the motion of the hand to the index E. This 

 is an index of paper, pasted on the pannel opposite to the hand, and so, as in 

 this figure, placed near the top, for the better convenience of the hand's motion; 

 and this index being but a quarter of a circle, is divided into inches, more or 

 fewer according to the scope which the hand of the pannels requires for their 

 motion; but when the relax shall require more room for the hand, then the 

 chain is to be taken up one link more, and thus there will be more play up- 

 wards and downwards : which taking up of the chain may yet be again repeated, 

 when there is occasion, or the time of the year requires it. 



Now if the chain be placed near the axis, the motion will be the nicer and 

 larger; if farther off then it will be less : For instance, the motion of 2 more 

 than that of 3, and 3 than that of 4, &c. as may be seen by the figures 2, 

 3, 4, 5, 6; which are placed in this figure below the hand. 



These pannels of deal board move by shrinking most in summer, and swell- 

 ing most in winter seasons ; but will vary from this, according to the greater 

 degree of heat or cold, moisture or drought. — For the most part, especially in 

 spring and summer, this motion happens only in the day time ; for then gene- 

 rally all night it rests and moves very seldom. — ^That one kind or manner of this 

 motion happens in dry fair weather ; but sometimes in the forepart of the fore- 

 noon, and sometimes not until the latter part of the forenoon, and then it re- 

 laxes or swells the deal for about two or three hours, more or less ; and then all 

 the afternoon it shrinks, sometimes even when a small rain has newly fallen or 

 is then falling; but this not so often, and more seldom in winter, or cold moist 

 weather. — ^This shrinking is very often gradual, or for the most part a little 

 after a moist time, viz. the first day after moisture it shrinks a little, the second 

 day more, and so still more according to the time of year, and as it is then in- 

 clined to moisture or drought, heat or cold. — The winds being in the north, 

 north-east and east, winter and summer, for the most part at that time the deal 

 shrinks in the night as well as in the day; but not so much : which is a sign of 



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