170 CATALOGUE. PHILOSOPHY AXD ARTS, PRACTICAL MECHANICS. 



Parent's statics with and without friction. A. 



P. 1704. 

 Sauveur on the friction of ropes coiled round 



a cylinder. A. P. 1703. 305. 



Sturm on friction. M. Berl. I. 294. 



Leibnitz on tlie resistance o^^achines. M. 



Berl. I. 307. 

 Varignon on the pressure of solids round 



which ropes are coiled. A. P. 1717- 195. 



n. 68. 

 Lcupold. Th. M. G. t. 30 . . 32. 

 Bulfinger'on friction. C. Petr. II. 403. 



Makes it i of the weight. 

 Desaguliers on friction. Ph. tr. 1732. 292. 



394. 

 Allows about \. 



Kuler on friction. A, Berl. 1748. ^122. 133. 



Euleronthe friction of revolving bodies. N. 



C. Petr.Vl. 233. 

 Euler on the pressure and friction of ropes. 



N. C. Petr. XX. 304. 327. 

 Musschenbroek Introductio. I. 145. 

 Schober Versuch ciner theorie von der iiber- 



wicht. 1752. 

 ♦Bernoulli on friction. N. C. Petr. XIV. i. 



249. 

 Emerson's mechanics. Pr. 118. 

 Meistcr. N. C Gott. I. 181. 

 Lambert on friction. A. Berl. 1771. 9- 177fi. 



3. 



Thinks it not constant, as commonly supposed, but 

 varying as the square of the velocity. 



Belidor. Arch. Hydr. 1. 70. 



Machine for experiments on the friction of 

 pivots. E. M. PI. III. Horlogerie. 



JjCDigez Esperienze intorno alia vesistenza del 

 fregamento. 8. Verona, 1782. 



Ximcfies Resistenze dei solidi. 



♦Coulomb. S. E. X. Account in Journ. 

 Phys. Sept. 178). 



*Vince on friction, and on the centre of fric- 

 tion. Ph. tr. 1785. 165. Ph. M. XVII. 47. 



The friction of bard bodies is a uniform force, that of 

 cloth increases with the velocity. The friction is greater 

 as the surface is greater, but not in any regular proportion. 



Metternkh dc frictione. 4. Erfurt, 1786. 

 Metternich von dem vviderstande der reibung. 



Maynz. 1789- 

 Burrow on friction. As. Res. I. 171. 

 Prony Architecture hydraulique. 

 Cavallo. N. Ph. I. 275. 



A block of 5 puUies, which with 150 pounds should raise 

 15O0, will barely draw up 500. 



Southern on friction. Ph. M. XVII. 120. 



In confirmation of Vince's observations. 



Abstract of CoulomVs memoir on friclion. S.E. 1785. X 

 161. 



This memoir received a prize from the academy of sci- 

 ences in 1 7 8 1 ; the experiments were made on a large scale, 

 at Rochfort, in 1779. 



Amontons thought that friction was nearly independent 

 of the extent of the surfaces. Musschenbroek ' found it 

 otherwise. 



At a maximum, that is, after resting some time, the fric- 

 tion, or rather the adhesion, is found to be, for oak on oak, 



from to —of the weight, according to the magnitude 



2.-28 3.39 



of the surface : for oak on fir ; for fir on fir ; for 



1.5 1.78 



elm : the fibres moving longitudinally. When they 



<2.18 



'1 

 cross at right angles, the friction of oak is -r-rr- For iron on 



1 



1 

 3.5 



oak -^: for iron on iron — : in this case the time of 



rest had no cfFect. For iron on brass — when the surfaces 







are well polished ; when larger, and not guite so smooth, 

 1 

 3.8' 



With tallow or grease on oak, some days were required to 

 obtain the maximum of friction or adhesion, when the sur- 

 faces were large : but when they were small it was very 

 soon acquired. This maximum was nearly the same at 

 without grease ; sometimes a little greater. The addition 

 from rest varied at first as the fifth root of the time. For 

 iron or copper with tallow, the increase during rest is less 



considerable : at first the friction is — of the weight, be- 



11 



