VOL. LI.] PHILOSOPHICAL TRANSACTIONS. 357 



20 turns of the sails raised the weight 1 1.3 inches. 



Velocity of the centre of the sails, in the circumference of the greatl ^ ^ 



circle, in a second J 



Continuance of the experiment 52 seconds. 



N° Wt. in the scale. Turns. Product. The weight of the scale and pulley was 3 oz. 



^ ? ^^^ ^ and 1 oz. suspended on one of the radii, at 



2 6 83 510 . , -^ , - , . ' 



3 Qi gj 526J 124-mches from the centre of the axis, just 



4 7 78 546 overcame the friction, scale, and load of 74- lb. 



5 7h 73 547s max. and placed at 14-la inches, overcame the same 



^ ^ "^ ^^^ resistance with Q lb. in the scale. 



7 9 



Reduction of the preceding Specimen. 



N° 5 being taken for the maximum, the weight in the scale was 7 lb. 8 oz. 

 which, with the weight of the scale and pulley 3 oz. makes 7 lb. 11 oz. equal to 

 123 oz. ; this added to the friction of the machinery, the sum is the whole resist- 

 ance.* The friction of the machinery is thus deduced: since 20 turns of the 

 sails raised the weight 11.3 inches, with a double line, the radius of the cylinder 

 will be .18 of an inch; but had the weight been raised by a single line, the 

 radius of the cylinder being half the former, viz. .09, the resistance would have 

 been the same: we shall therefore have this analogy; as half the radius of the 

 cylinder, is to the length of the arm where the small weight was applied; so is 

 the weight applied to the arm, to a 4th weight, which is equivalent to the sum 

 of the whole resistance together; that is, .09 : 12.5 :: 1 oz. : 139 oz.; this exceeds 

 123 oz. the weight in the scale, by 16 oz. or 1 lb. which is equivalent to the 

 friction; and which, added to the above weight of 7 lb. 11 oz. makes 8 lb. 11 oz. 

 =z= 8.69 lb. for the sum of the whole resistance; and this, multiplied by 73 turns, 

 makes a product of 634, which may be called the representative of the effect 

 produced. 



In like manner, if the weight 9 lb. which caused the sails to rest after being 

 in motion, be augmented by the weight of the scale and its relative friction, it 

 will become 10.37 lb. The result of this specimen is set down in N° 12 of 

 table 3, and the result of every other set of experiments there contained, were 

 made and reduced in the same manner. 



* The resistance of the air is not taken into the account of resistance, because it is inseparable 

 from the application of the power.— Orig. 



