PULP INSULATION FOR TELEPHONE CABLES 5 



after some preliminary experiments gave sufficient promise of success 

 to suggest the desirability of going ahead with the development of 

 the idea and the mechanism to carry it out. 



A crude paper machine of the cylinder type was built and with this 

 the feasibility of the basic idea was demonstrated. Dryers were next 

 improvised and sufficient wire was insulated to give a few short test 

 cables. These, of course, were made from carefully selected insulation 

 for only a small part of the wire made was usable. The test results on 

 these cables were sufficiently interesting to warrant proceeding further 

 with the project. After considerable study and experiment it was 

 decided to build a ten-wire machine adaptable to future expansion if 



Fig. 3 — Wire supply and pulp preparation equipment. 



the anticipated results were realized. This ten-wire machine was 

 started up with very indifferent success in January-, 1924. During 

 that year an operating technique was gradually developed and 

 numerous improvements made in the equipment. In 1925, a great 

 many test cables were made and several were installed for use in the 

 telephone plant. Experience with the ten-wire operation and product 

 finally became so satisfactory that it was decided to expand the 

 machine to a fifty-wire capacity and put it on as near a commercial 

 basis as possible, in order that its operation, product and economics 

 might be studied to better advantage. Accordingly, the necessary 



