30 Field Museum of Natural History — Reports, Vol. III. 



swinging lights of plate glass 68x70 inches in size. The interiors 

 are fitted with shelves supported by metal brackets, which are screwed 

 to strips of strap-iron having holes at intervals of one inch. The 

 shelving is thus adjustable at small intervals of height or width to 

 suit the demands of installation. The interiors of the cases are lined 

 with painter's muslin stretched tightly and painted black, giving a 

 smooth, even finish. The specimens are installed immediately upon 

 the shelves. The labels are supported by individual wooden strips in 

 which slots are cut. The floor cases are made as in paleontology, so 

 that the small specimens can be easily and thoroughly examined. 

 For this purpose it is obviously necessary to bring the specimen to 

 the height of the eye and as little removed from it laterally as possible. 

 Cases of the "A" type best meet this requirement and at the same time 

 provide more exhibition space to a given amount of floor space than 

 a flat case. The cases adopted for this purpose were made four inches 

 higher than those used in paleontology and the exhibition portion 

 carried three inches lower. Thus, increased exhibition space was 

 gained, the lights being 36 x 58 inches in size, as compared with those 

 31x56 inches used previously. It having been found that ground 

 glass, as hitherto used in the top and ends, was not necessary for 

 lighting, wooden panels were used in its place, thus securing an effect 

 of greater richness and solidity. Triangular wooden screens occupy 

 the interior of the case as before, and upon these the minerals are 

 installed. Each specimen occupies an individual block which is 

 fastened to the screen. The blocks used vary in size, according to 

 the size of the specimen. The front of each block is beveled and 

 provided with a bead which supports the label. All the case interiors 

 are black and the labels are black cardboard, printed with aluminum 

 ink. The plan of keeping the fittings and labels subordinate in general 

 to the specimens themselves is thus maintained and a satisfactory 

 and attractive effect secured. The floor cases are, as stated, reserved 

 for specimens so small as to require close inspection in order to have their 

 features of interest revealed. The collections were completely worked 

 over before installation, so as to incorporate all new material and weed 

 out duplicates from the exhibition series. About ten thousand speci- 

 mens are now on exhibition in this collection. For the collection 

 illustrating structural geology only wall cases are employed, since 

 these are exceptionally adapted to the exhibition of large specimens 

 and the collection is mostly of this character. The specimens as 

 thus installed are well lighted and the hall makes a very satisfactory 



