ABRASION OF THE SURFACES OF SOLIDS. %^ 



Experiments on the Friction of Axles without and with Unguents. 



Weight on Axle. Weight required to move it. 



Time. 



Proportion. Space passed over. 



Yellow Brass on Cast Iron with Tallow. 



cwt, 

 1 

 2 

 3 

 4 

 5 



sec. 

 90 



36.57 

 38.95 

 40.42 

 40.49 

 40.72 



4§ inches. 



Yellow Brass on Cast Iron with Soft-soap. 



cwt. 

 J. 



2 

 1 



2 

 3 

 4 



lbs. oz. 

 2 2 



3 



6 



9 



12 



14 



8 







8 



12 



12 



90 



26.35 

 32.00 

 37.33 

 35.36 

 35.13 

 37.96 



4§ inches. 



Yellow Brass on Cast Iron with Soft-soap and Black-lead. 



cwt. 

 i. 



2 

 1 



2 

 3 

 4 

 5 



lbs. oz. 

 5 8 



9 

 12 

 14 



19 8 

 23 8 



90 



10.18 

 12.19 

 18.56 

 23.57 



22.97 

 23.82 



4i inches. 



Remarks on the experiments without Unguents. 



Frotn the foregoing experiments it appears, — 



That when gun metal without unguents is loaded with variable weights of from 1 to 10 cwt., friction 

 varies nearly in the proportion of y.^y to -^.j-q of the pressure. 

 That length of time scarcely affects it. 

 That friction increased when yellow brass was tried. 

 Tliat friction decreased when cast iron was tried. 

 That friction diminished still more when black-lead was used between the three different metals. 



Remarks on the experiments with Unguents. 



That gun metal on cast iron, with oil intervening and a weight of 10 cwt., amounted to j.>^y of the 

 pressure. 



That when the insistent weights were diminished, the friction with oil was reduced to j^'y^, but 

 increased with an increase of weight. 



That cast iron on cast iron, under similar circumstances, showed less friction. 



y 2 



