i86 THE RUBBER TREE BOOK 



efficiency of both. Hence no apology should be necessary for 

 introducing the foregoing remarks. 



The manufacturing of the coagulated latex involves a 

 very severe strain on the washing-mills, and this is to some 

 extent indicated by the fact that, although they are compara- 

 tively small in size, it takes about 9 to 10 horse-power to drive 

 them when rolling sheets of crepe. It is necessary, therefore, 

 that the mills be of very solid construction, or they would soon 

 give way. British engineers may not be so clever in devising 

 ingenious labour-saving machinery as our American cousins, 

 but they build strong to last long, a merit American engineers 

 cannot so generally claim. A good width of rollers is a great 

 advantage, and 18 in. by 12 in. is a good size. Wide rollers 

 are advantageous in that more rubber can be manufactured 

 during working hours, and there is also much less likelihood of 

 any oil from the bearings getting into the rubber being rolled. 

 By means of various patented adjustments the space between 

 the rollers is easily increased or diminished without being greater 

 or less at one side of the rollers than it is at the other side. 



The difference between the speed at which the two rollers 

 in the mills revolve can be too great or too little. The greater 

 it is, the greater is the violence with which shredding and tear- 

 ing the sheets of rubber proceeds. Experience has enabled 

 engineers to arrive at a reasonable adjustment in this respect. 



Rollers for macerating and creping mills should have their 

 patterns or grooves at least Jth of an inch deep. This is the 

 absolute minimum depth ; r \ths of an inch is by no means too 

 deep. Now, it is very expensive work to cut these patterns or 

 grooves. The metal of the rollers is so very hard that a file 

 makes almost no impression. Evidently, then, the less the depth 

 an engineering firm has to cut out these rollers to, the more 

 money it will save. In several instances rollers have therefore 

 been sent out to estates in the East cut out to a depth of only 

 i^th of an inch. These have been dispatched by more than one 

 leading firm of engineers. Such rollers are practically useless. 

 If any manager receives such he should refuse delivery right 

 away. Owing to the shallow depth when the patterns on 

 rollers are only T Vth of an inch deep, they cannot do their 

 work properly. Instead of tearing, shredding and creping the 

 sheets of rubber, and at the same time properly cleansing it, 



