Miscellaneous Intelligence. 91 



only for very fragile and delicate specimens, but would at the 

 same time serve to keep in perfect position specimens of con- 

 siderable weight and size. It was imperatively necessary to 

 secure such specimens from even the slightest bending. 



The Blaschka glass models of plants in flower are shipped to 

 our Museum fastened to a firm cardboard which answers every 

 purpose as a permanent mount for the smaller species. But even 

 when re-enforced by strips of wood, the larger plates of card- 

 board have a tendency to curve, sometimes in more than two 

 directions, and this curvature seemed likely to put the larger 

 models in some peril of breaking. 



Acting on a suggestion of Dr. Libbey of Boston, an attempt 

 was made, about six years ago, to substitute plaster-plates for the 

 heavy cardboard. More than a year was consumed in fruitless 

 experimenting. The small plates were fairly strong and for the 

 most part, satisfactory, but the larger ones, say from two feet 

 square and upward, were untrustworthy and therefore of no use 

 in our cases. 



Fortunately, at the time when our experiments were on the 

 eve of abandonment, there was in the service of the Museum an 

 expert cabinet-maker who expressed a desire to undertake a con- 

 tinuation of the work along a different line. After a few trials 

 which varied in success, he was able to produce plaques of high 

 finish and great density. Tests showed that these new plaques 

 were sufficiently strong to bear any weight to which it was likely 

 they could ever be subjected, and moreover, they did not show 

 the least tendency to bend. About fifty were made four years 

 ago, and, after they had been exposed to all reasonable risks, it 

 was found that they had not sustained any permanent injury of 

 any sort. During the last three years, more than seven hundred 

 plates have been successfully made, and these are now installed 

 in the exhibition rooms of the botanical section of the Museum. 

 They are so strong, so free from curvature and so attractive in 

 general appearance, that they appear to answer every require- 

 ment as mounts. 



The following is the method of their manufacture: 



(1) The appliances. . On a stout table perfectly levelled there 

 is placed a plate of the finest plate-glass of the required size. On 

 our tables we have used glass of a convenient size for our work, 

 namely four by three feet, and five by four feet. Care is taken 

 to choose only " first " plate: " seconds " are likely to have small 

 blow-holes or slight curvatures. For each plate on the table 

 another of equal size and of about the same thickness is placed 

 near at hand. 



In order to form a dam around the sides of the glass, to pre- 

 vent the plaster from running off, we have used strips of wood 

 of just the thickness of the desired plaque. These are simply 

 put in place and not fastened to the glass in any way. 



(2) The liquid plaster is made in the following way : into a 

 large pail of j:>erfectly clear soft water, enough fine plaster of 



