Hydraulic Bivestigaiions. \ £3 



stance carefully converted into charcoal, and afterwards ap- 

 s plied to the same purpose. The substances being so varied 

 and numerous that contain the oxide of carbon, it could not 

 possibly follow that the extent of their carbonaceous effects 

 would be in the proportion of their masses under similar 

 circumstances, nor that the charcoal or oxide that each of 

 them afforded by distillation would bear the same relation 

 to each other in point of purity, even where the acknow- 

 ledged quantity of alloy in the state of earths, salts, &c, 

 were the same. We therefore find, that even in the state of 

 the raw substance equal weights or quantities of matter, 

 calculating always upon the residuum alloys of different 

 substances, produce results materially different, which can 

 only be attributable to the different existing stale of the 

 oxide, or to the decomposition of the hydro-carbonate which 

 most of them contain. The difference of the results becomes 

 much greater when the oxide of carbon is used in the state 

 of charcoal or coke, and the variety of the results here also 

 obtained, where no hydro-carbonate comes into action, can 

 only be placed to the state of oxidation of the carbon. 



In a future communication I shall illustrate, by some ex- 

 periments, what I have just stated. 



XX. Hydraulic Investigations, subservient to an intended 

 Croonian Lecture on the Motion of the Blood. By Thos. 

 Young, M.D. Fur. Sec. R.S* 



I. Of the Friction and Discharge of Fluids running in Pipes 9 

 and of the Velocity of Rivers. 



Waving lately fixed on the discussion of the nature of in- 

 flammation, for the subject or an academical exercise, I 

 found it necessary to examine attentively the mechanical 

 principles of the circulation of the blood, and to investigate 

 minutely and comprehensively the motion of fluids in pipes, 

 as affected by friction, the resistance occasioned by flexure, 

 }he laws of the propagation of an impulse through the fluid 



* From Philosophical Transactions for 1808. 



contained 



