454 Review of Dr. Wetherill’s Treatise, §c. 
have a chance each time to empty themselves partially of liquid and 
become filled with air; and the air will thus be brought into more inti- 
mate contact with the liquor of the next pouring. While with a con- 
stant flow, the air will be present only in the interstices and not in the 
pores. Our author very justly considers that pouring at intervals would 
be preferable to the constant flow, if it could be effected without the 
great amount of care and manual labor casa it commonly requires. He 
probably is not aware axe there has tec in some manufactories in 
of sheet copper, it is s able to obvious objection The writer has had 
Tie 2 shows the in- 
side of the end piece with i 
dove-tail grooves 
whole of the oscillator itself 
the triangles a bc, the side ac 
is 74 inches ris ab is 6 inches 
and 6¢ is 7 inches, e sides 
of the box a are 134 inches 
ge ae inlnding the dove- 
ail tongu Th 
or angular groove on each side 
to receive the lower edges f 
the side pieces d. These si 
pieces are held fast by the . 
- An indentation on the 
a. the oe may be still father adj lasses by varying the height 
of the cushions & on which the sides d ac whole nied 
be w aia before it is set on a sieve hea 
