216 CAOUTCHOUC AND GUTTA-PERCHA. 
by fresh additions to it during the process of rolling. In order that the sheets 
be prevented from sticking to each other, they are, when taken from the rollers, 
placed into cold water or strewn over by tale powder. When placed between 
textures or covered with them on one side, and then passed between rollers, 
caoutcboue and texture adhere to each other, thus yiclding a very dgrable 
water-proof material, which is not, however, free from defects. By pressing the 
edges together, while heated, the caoutchoue sheets become perteetly united, 
so that in this way various utensils, bags, &c., of all dimensions, can easily 
be manufactured of them. This property made Howisse believe that we 
could soon do without tailors. According to him, instead of being sewed, the 
edges of the single pieces of a dress are to be besmeared with caoutchouc and 
pressed together. 
Plates of caoutchouc and gutta-percha are easily cut into threads and rib- 
bons of any thickness by two spiral blades of a peculiar cutting machine. In 
order to facilitate the weaving of caoutchouc threads, they are made non- 
elastic by stretching and cooling. The finished texture being heated to a tem- 
perature of 45°, the caoutchoue regains its former elasticity. Both eaoutchouc 
and gutta-percha can also be drawn into very fine uniform threads by means of 
a drawing iron, the material being swelled up in sulphuretted carbon, contain- 
ing an admixture of alcohol. hick threads can be stretched into thin ones of 
six times their length, and when heated to a temperature of 100° they preserve 
the length obtained by stretching. After cooling, the same process can again 
and again be repeated, until the desired thinness is obtained. After six repe- 
titions, for instance, the length obtained is already like 16,625 to 1, representing 
the original length. Such thin threads of gutta-percha are particularly to be 
recommended as twine to artistic gardeners. ‘Their pliability and strength are 
astonishing. Plaitings derived from them seem to be indestructible. 
When caoutchouc is to be used as dough or cement, it is first made to swell 
in about double its weight of the solvent, and the jelly is then crushed ina 
machine by means of several cylinders. This mass serves either as glue, as, for 
instance, in the manufacture of cabinet ware and musical instruments, or to make 
certain materials water-proof, or to save them from moisture, as, for instance, 
the wainscot of buildings. After the example of England, German bookbinders, 
too, use caoutchouc, instead of animal glue, to great advantage. A caoutchoue 
cement, known under the name of mairne glue, has evinced some excellent 
qualities, especially in joints of wood and metals exposed to water, as well 
as for calking purposes. A solution of caoutchoue and rapeseed oil, which 
absorbs of the former only a one-hundredth part of its own weight, is used as 
grease for parts of machines exposed to excessive friction. When slaked lime 
is added to the softened mass which caoutchouc yields at a temperature of 210°, 
an excellent water-proof cement is obtained. ‘Though tough, the mass remains 
kneadable for years; an admixture of vermillion is, therefore, necessary when 
drying up is desired. 
A solution of caoutchoue and gutta-percha, has various useful applications, 
among others for coating various substances in order to make them water- 
proof or to save them from the influence of water and air, as, for instance, in 
the manufacture of leather, shoes, and boots, leather and hemp bags, cordage, 
&c. A solution of gutta-percha in chloroform is more serviceable in euring 
wounds than collodion, which it will undoubtedly replace also in photography. 
Within this narrow sphere the cdoutchoue industry but a few years ago 
moved. ‘I'he discovery of the remarkable relation of this substance to sulphur 
finally removed all defects from the articles obtained by its manufacture. ‘The 
English manufacturer, Hancock, early discovered that the hardened vegetable 
juice enters into a chemical combination with sulphur, which greatly alters the 
property of the former, and makes it entirely indifferent to the influences of the 
temperature. Under all circumstances the principal property, elasticity, re- 
