and Laboratory Methods. 



2607 



has used with splendid results, brass rods socketted in mahogany blocks (Fig. 90). 

 For mineral masses, stands of ebonized wood or of mahogany are superior (Fig. 

 91), but oak, chestnut and black walnut can be favorably used. On steeply slant- 

 ing shelves the label block can be used as a support to the object, or, in the case 

 of large shells, a V-shaped collar. Devices are innumerable for meeting such 

 problems, and the skill and taste of the exhibitor can be indefinitely exercised. 

 A pin is a form of support, whether it transfixes an insect, or holds up the 

 end of a chinook blanket, or restrains a clam shell from sliding off an inclined 

 board, or exhibits, poster-like, a label, or more differentiated still, with three 

 clamps, grasps a gem. Pin, therefore, is a generic term for metal appurtenances 

 so modified as to meet these different uses. Rods run along the tops of cases, 

 form a convenient rack for the suspension of pictures, maps, etc. The rods are 

 held by staples in the roof of the case. 



Fig. 111. — Sulphur from Cianciani, Italy. 



JARS, PLASTER AND GLASS CELLS. 



The plaster cells of Denton for lepidoptera are probably one of the most 

 notable inventions in museum installation proposed in the last ten years. They 

 consist in a white plaster block, with a depressed pit holding the body of the 

 insect, whose wings are outstretched, the whole sealed in by a glass cover. 

 Glass cells for food products, medicines, herb preparations, etc., can be formed 

 from five glass plates cemented together by soluble glass, and covered by a glass 

 slide moving on vaseline. A more elaborate form consists of four glass plates 

 socketed in wood, with a glass cover held on by metal pins, which pass through 

 the glass, and can be unscrewed, their ends being driven in the wooden frame 

 at the bottom of the cell. 



Glass jars for alcoholics should almost invariably be flat with black painted 

 backs, so that the bleached or diaphanous objects, contained in them, can be 

 clearly seen. Flat glass jars are expensive, but it seems likely that the less 

 munificent managements can make their own jars from glass panes held together 



