200 



APPENDIX. 



The same depth and number of paddles being taken as before, this amount of surface gives 

 a breadth of 10'56 inches. Mr. Mornay calculates it 10'6 inches. 

 The requisite POWER OF THE ENGINE may now be found as follows : 



log. 



log. V 2 



A' 



SV 



" 1000 



2-93920 

 9-86988 



0-01621 



2-82529 

 668-79 



log. Vt> 2-54709 



B' 9-92350 



0-01621 



2-48680 



306-76 



Mr. Mornay's calculation is 199'31 horse power. 



B 



2-15498 

 9-98677 

 0-01621 



2-15796 



143-87 

 668-79 



812-66 

 613-52 



Horsepower 199"14 



3. OLDHAM'S WHEEL. 



Taking the same data as in the first example, let it be required to determine the requisite 

 amount of PADDLE SURFACE (S) on each wheel. 



log. a 0-69897 V = 14-530 



=. 0-54054 



k 



0-96614 



- 9-73283 



v = 11-953 



V-t>= 2-577 



- ^ 0-45946 



;- 5-54054 



(V - ) 

 v 



i ditto 

 log. 



log. 



9-66225 



9-83113 

 0-74355 



9-43416 



0-00884 

 0-82222 

 1-07749 



1-90855 



Effective 1 



VT c \ 88-33 log. 

 Power / 



1-94611 

 1-90855 



0-03756 



1000 



.-. S = 1090-3 feet. 



This wheel, therefore, requires a much larger surface of paddle than the common wheel. 

 Indeed, under any given circumstances, the common wheel may be said to possess the advan- 

 tages of requiring the least surface of paddle to produce a given effect, and of encumbering the 

 action with the least possible amount of friction and strain on the bearings, which are recom- 

 mendations of a very strong character. 



VI. ON THE ACTUAL RESISTANCE OF BOATS ON CANALS. 



The experiments alluded to in the foot-note, page 297, were made by John Mac- 

 neill, Esq., C.E., &c., in July 1834, on two canals in Scotland, with the boats actually used 

 in the traffic on those canals ; and from a scientific gentleman of such universally acknowledged 

 ability and experience, they are deserving of the greatest reliance. The experiments, which 



