2602 



Journal of Applied Microscopy 



either under a flat case or in the higher tiers, in storage and duplicate rooms, is 

 shut in behind an outer door, it is often convenient, especially in the study rooms, 

 to make this outer door a glass door, so that labels and descriptions of contents 

 on the drawers behind can be read without the annoyance of opening the door 

 itself for such a purpose. 



The painted tin-can for the preservation of study collections in ornithology 

 and mammalogy is important. Their use is of course general. They consist of 

 a box with an upper edge provided with a gutter into which the cover fits, press- 

 ing down upon a rubber strip at the bottom of the gutter, thus insuring air-tight- 

 ness. The dosing of the contents from time to time with bi-sulphide of carbon, 



Fig. 85. — Tin cans for preservation of skins, etc. 



in conjunction with this hermetical seal, seems to provide an indefinitely long 

 (Fig. 85) life to very perishable objects. 



Turnstiles are invaluable adjuncts to cases, and for some objects or exhibits 

 are absolutely indispensable. In the British Museum such turnstiles contain the 

 mounted specimens of local herbaria, and Dr. Britton will put them to an iden- 

 tical use in the Museum of Botany in the Botanical Gardens in New York. For 

 photographs, illustrative plates — as once employed by Pres. Jesup for his wood 

 collection — they form the only convenient means of accommodation for a large 

 series of planular objects. They should be simple and strong. An effective 

 turnstile designed by the writer is shown in Fig. 86. The central part is on ball- 

 bearings, enclosed in the box A, so that the visitor can at will revolve the post 



