72 NATURALISTS’ ASSISTANT. 
strip of cotton wool has been tacked to the door, at oth- 
ers the door and frame are fitted with tongue and groove. 
This is possibly the best method and is employed in the Yale 
cases. A cheap means has been adopted at the Peabody 
Academy of Science with good results. A thin strip of rub- 
ber packing is folded and fastened by means of a strip of 
wood to the case and against this fold the door closes sending 
the joint all but air- 
tight. The construc- 
tion is readily seen from 
figure 23. The floor of 
a vertical case should 
be some few inches 
above the floor of the 
exhibition room, and the space 
thus left may be occupied by 
drawers for the storage of speci- 
mens. ‘The shelves in an upright 
case should be adjustable to any 
Bie23) desired height. A perfect method 
of accomplishing this yet remains to be invented. Sometimes 
sticks fitting into ratchets on which the shelves are supported 
are employed, others support the shelves on “screw eyes”’ 
screwed into the frame of the case. But doubtless the best 
apparatus is the adjustable brackets. ‘Two patterns of these 
are made, one by Mr. Jenks and one by Mr. Gavitt, each 
having its merits and objections. Possibly the former is 
preferable. Each of these employs an iron bracket (hori- 
-catal or inclined as may be desired) which hooks into an 
