Sor the Advancement of Science. 389 
no means indicates, it is obvious, the real velocity of the wave, as the; — 
ship meanwhile was advancing nearly in the same direction at the rate — 
a 
-! obliquity: of two points we have 231°5 feet to be added to the former. 
measure, five hundred and fifty nine feet, which gives 730:5 feet for the: 
actual distance traversed by the wave in 16°5 seconds of:time, being at. 
yen 
hee 
the rate of ae =) 17,251°7 feet, or 32°67 English state 
a 
hour. To know how far this result is but proximate, it» 
Known magnitudes, to estimate certain distances with all but perfect ac- 
cy hus, as to a circumstance in which we were most deeply in- 
0 
