62 PHILOSOPHICAL TRANSACTIONS. [anNO 1684. 



section LQD, the heavier ought the counterpoise P to be; and that either in 

 its own intrinsic weight, in ounces, &c. or else in its potential weight, by being 

 raised higher in the quadrant QT. *] . The screwing up the stage of the move- 

 ment at S, will raise the counterpoise higher in the quadrant QT, by prop. 3, 

 and therefore make it potentially heavier. From hence appears both the reason 

 of the due adjustment of the motion of the train to the exact measure of an 

 hour, and what weight is to be assigned to P, that moves it. Therefore having 

 set the stage, by the help of the arched screw, at the elevation of about 10 de- 

 grees, place the movement thereon, and try what weight, hanging at the end 

 of the lever MP, will stir the train ; meanwhile holding the movement with 

 the hand in such a position, as that the level may make an angle of about 30 

 degrees with the perpendicular MT: then let the movement loose, to vmdulate 

 upon the stage ; and when the vibration ceases, observe to what degree of the 

 quadrant the lever points, and at the same time mind the pulses of the balance. 

 If, at this observation, the weight lies low, as for instance between 25 and 35 

 degrees of the quadrant, and the beats of the balance are guessed to be not very 

 different from their due time, the weight P is well enough proportioned ; but if 

 it chance to be much heavier than is absolutely needful, that excess will be mode- 

 rated by screwing down the stage; and if it be not absolutely too light, its de- 

 fect will be compensated, by screwing the stage higher. Therefore of these 

 two extremes, chuse the former; for the fewer degrees P rises in the quadrant 

 beyond what is absolutely necessary, the better. 



Experiments to be made relating to Land Carriage. Proposed by Sir William 



Petty, Knt. N° l6], p, 6QQ. 



The water carriage of goods round the globe of the earth, is but about double 

 the price of land carriage from Chester to London of the like goods. Land 

 carriage by carts and waggons is cheaper than on horses backs, and this cheaper 

 than by men. Therefore carriage by carts and waggons ought to be well under- 

 stood and considered. 



Land carnage by draught, is by wheel-barrows, straddles, carts of 1 wheels, 

 sleds, waggons of 4 wheels, by cars on 2 high wheels, drays on 1 small wheels, 

 Irish cars of 2 very small wheels. The present work is to design experiments 

 whereby to know the difference and advantages of all the said several carriages, 

 upon several ways and grounds. To which purpose it is proposed that the fol- 

 lowing experiments be made, viz. 



Exper. ] . — The difference between what a man or horse can carry, and what 

 they can draw up at a pulley. — 2. The difference in what a man can carry for 1, 



