REPORT OF THE DIRECTOR I918 225 



a gradual and even pressure, so essential in overcoming the difficulty 

 of boring through many cleavage planes which were always a constant 

 source of trouble. With this procedure, out of all the lot, just two 

 crystals failed us. Thin slabs composed of clusters of small crystals 

 were drilled entirely through. An iron bolt with a loop at one end 

 was fastened in these holes by means of a nut and washer on both 

 the face and back of the specimen. The exposed nut on the face of 

 these clusters was easily hidden by matching a small crystal over it. 

 The larger specimens, however, were bored for a depth of only 2 

 inches and in each hole was set a i| inch screw eye; the heaviest 

 crystals necessitating special heavy irons of the same shape. By 

 pouring melted sulphur in the hole and immediately plunging into it 

 a red hot screw eye, we had a means of support, when cold, by which 

 the crystals could be wired in any position to the iron framework. 

 Many times the distance between the iron ribs was too great and 

 necessitated spanning these spaces with three-fourths inch or ij 

 inch band iron. 



The actual placing in pDsition of the crystals was started at the 

 deepest point, which -was around the mirror. Small areas of the 

 frame were covered as needed with galvanized iron wire screen of 

 one-fourth inch mesh. After a crystal had been securely wired to 

 the framework, a combination of cheese cloth and plaster woven 

 over the wires and frame between the screen and crystal held it 

 permanently in the exact position desired. This same process was 

 continued gradually around the sides and roof to the window. 



Each time a crystal was placed there were three points to consider : 

 Did it fit exactly to the one next to it ? Were the best crystal faces 

 seen, not only looking directly at it but in each of the two mirrors? 

 Was it possible to place behind it an electric light which could not 

 be seen from three sides? These questions arose simultaneously 

 nearly every time and the solution was simply the answer given by 

 trying out each of them. 



The construction of the floor was the last and comparatively the 

 easiest operation. Two-inch spruce planking was laid over the 

 floor girders to carry this great weight as the largest crystals of the 

 original cave were found on the bottom, many of them entirely free 

 on all sides and apparently with no surface of attachment. For this 

 reason it was not necessary to place these so close together, which 

 gave a good deal of leeway for electric lights with shades. 



We have carefully shaded a system of twenty-one lights ranging 

 from 10 to 60 Watt, which have been placed behind the most highly 



