208 PENDULE A TRÉS-LONGUE PÉRIODE. 
nally when the inclinations were the greatest, the difference 
was as much as 4°. The automatic record always gave the 
smaller angles; and it is easy to see that this is almost a 
necessary consequence of the mode of observation, — 
because the observer cannot anticipate with exactness 
the change of motion which the wave is preparing to 
impress on the ship, and is therefore too slow in accom- 
panyingit.... 
Wam FROUDE. 
Chelston Cross, Torquay, December, 22th, 1872. 
