472 
this report. Much of my time was spent in acquiring knowledge 
* of these details in the various factories I visited. Three facts must 
be remembered in order to properly understand the final manufac- 
ture of rubber goods. The dough of masticated rubber, mixed with 
sulphur and other ingredients, is plastic and has lost the original 
elasticity of rubber. It can be cut and moulded, stamped into 
shapes, bent and twisted, just a? putty, clay, or a dough of flour 
and water may. Rubber dough and masticated rubber are self 
adhesive, and cut surfaces can be joined firmly together by simple 
pressure, and if the surfaces be brushed over with benzole the pres- 
sure required to form a very firm junction is of the slightest. On 
Hhating the dough and masticated rubber which contains sulphur, 
a chemical change takes place and a chemical compound of rubber 
and sulphur is formed which possesses the original elasticity and 
toughness of the raw rubber, but in a greater and more perfect 
degree. This chemical change is called vulcanisation of the rub- 
ber, and it is- the final process to which practically all manufactured 
rubber goods are put. It must never be forgotten that raw rubber 
and vulcanised rubber are quite different and distinct substances, 
their chemical compositions are different, their properties both 
physical and chemical are quite distinct, and moreover though the 
change from raw rubber to the sulphur compound of rubber — that 
is, vulcanised rubber — can be easily effected by simple mixing and 
heating to 300° F., the reverse process of removing the sulphur and 
reforming raw rubber has never yet been done. 
27. The vulcanised rubber goods which the manufacturer 
turns out may be divided into three main classes -I, stamped and 
moulded goods; II, goods built up of rubber dough and other 
material; and III, sheeted and spread rubber goods. 
Stamped Good£. 
28. All solid rubber articles — such as heel pads, soles for shoes, 
vulcanite stoppers, rubber rings, washers, mats, buffers and rubber 
pads, billiard cushions, rubber tube, etc.,— are prepared direct from 
the dough by stamping them out by hand or by machines, coating 
them with french chalk to prevent adhesion, and then vulcanising 
simply by heating on trays or in iron moulds. The variety of 
goods of this kind is enormous and without limit, and doughs of 
most diverse composition from pure rubber and sulphur to mixtures 
where rubber is present in very small proportion, are used for this 
kind of work. This branch of the manufacture of rubber goods is 
as simple to understand as the art of the pastry cook, who stamps 
out fancifully shaped little cakes, or twists up curly bread, dredges 
with flour and bakes in an oven. The secrets are in the recipes tor 
the dough, and the art in the manner of making the shapes and 
regulating the baking. There are many ingenious and complicated 
machines used to save labour, but some of the simplest articles no 
machine can yet produce, and hand labour has to be employed. 
Rubber rings of circular cross section, commonly called ‘ umbrella 
rings,” have all to be made up by hand. If stamped or moulded 
the strength is not to be relied upon. The mode of making is 
