THE PREPARATION OF PLASTIC MASSES FROM CASEIN. 115 



articles are now made of galalith in Vienna, Gablonz arid 

 Nuremberg. 



By treating it in suitable presses, galalith is also made up 

 into backs for brushes, hairpins, rings and fancy articles, and 

 it is also made in sheets for combs of all kinds. As a rule 

 the mass is pressed before treating it with formaldehyde, but 

 for thin articles this procedure may be reversed. 



Dr. Hassack and his assistant, Sudey, are engaged in 

 making comparative tests with galalith and celluloid; and 

 up to the present the following particulars may be given. 

 The two substances agree closely in specific gravity, that of 

 galalith being 1-317 to T35, according to the admixtures 

 present, whilst celluloid is T34 to 1*4. In point of hardness 

 galalith is a little inferior to calc spar, namely, 2 -5, whilst 

 that of celluloid is below 2 ; and this substance can be 

 scratched by gypsum. One important difference in the 

 working qualities is that while celluloid can be easily cut 

 with a knife, galalith is hard to cut, and chips a good deal. 

 With the saw or on the lathe they can both be worked well, 

 but galalith the less easily on account of its greater hardness. 

 Both polish well, but galalith the better of the two, giving a 

 higher gloss. Celluloid is more elastic, thin sheets and rods 

 recovering their original shape at once when bent or rolled, 

 whereas galalith sheets or rods are brittle when bent. Gal- 

 alith also has the drawback that it cannot at present be 

 produced in sheets less than about T V inch thick; unlike 

 celluloid, in transparent sheets as thin as paper, and in fine 

 threads. Neither can the sheets be obtained perfectly clear 

 like glass ; nor is it so plastic as celluloid though it becomes 

 .soft, like horn, on prolonged soaking in boiling water. It 

 gradually absorbs a good deal of water when soaked, viz., 

 according to experimental results, 30 per cent, in six days at 

 room temperature, and 33 per cent, in twelve days, in which 

 process it swells and becomes like cheese, whereas celluloid 



