The principal processes employed in a rubber factory begin with the washing and drying of the crude commercial samples, which require thorough cleansing in order that technically pure rubber may be obtained. From this point two series of operations diverge, which may be distinguished as wet and dry processes respectively. In the former the rubber is dissolved in naphtha or benzene, and is then deposited from the solution in moulds or on cloth. The articles so formed are subsequently vulcanised, often by the cold process, i.e. the action of sulphur monochloride. The bulk of the larger and more solid goods are manufactured by a dry process. In this the rubber is first masticated or kneaded, in order to bring it into a suitable condition for the next operation, that of mixing, in which various filling and diluting materials are intimately distributed through the substance of the rubber, together with the sulphur required for vulcanisation. The mixed rubber is then moulded or forced or built up with layers of canvas into the various articles which are being made in the factory. Vulcanisation is subsequently carried out by steam heat in moulds or presses or closed chambers. Certain other articles again are cut out of rubber already vulcanised.