MECHANICS AND USEFUL ARTS. 93 



to the action of a mincing cylinder, somewhat similar to that used by 

 paper makers for the conversion of rags into pulp ; afterwards, the 

 whole is thoroughly cleaned in cold water tanks ; and when the gutta- 

 percha is found to be very impure, which is frequently the case as an 

 article of commerce, a solution of common soda or chloride of lime is 

 added to the water. From the cold water tanks the material is con- 

 veyed to the masticating machine, in which it is secured by the doors 

 being bolted down. By this operation it is subjected to very great 

 pressure, and this part of the process is the same as that used in the 

 manufacture of caoutchouc. From the masticating machine it is 



^5 



passed between large metal rollers, and thus converted into extensive 

 sheets, of thicknesses regulated by the distance between the rollers. 

 Sometimes it is passed two or three times between the rollers. These 

 sheets are cut into bands of various widths by vertical knives placed 

 at the end of the web or cloth by which the sheets are moved away 

 from the rollers. The sheets are either cut into the proper width for 

 lathe bands, or are stamped out for shoe soles, and various other 

 purposes. 



MANUFACTURE OF COMBS. 



THE greatest comb manufactory in the world is in Aberdeen, Scot- 

 land ; it is that of Messrs. Stewart, Rowell & Co. There are 36 fur- 

 naces for preparing horns and tortoise-shell for the combs, and no less 

 than 120 iron screw presses are continually going in stamping them. 

 Steam power is employed to cut the combs, and an engine of fifty 

 horse power is barely sufficient to do the work. The coarse combs 

 are stamped or cut out-- two being cut in one piece at a time, by a 

 machine invented in England in 1828. The fine dressing combs and 

 all small tooth combs, are cut bv fine circular saws, some so fine as to 



tt 



cut 40 teeth in the space of one inch, and they revolve 5,000 times in 

 a minute. There are 1,928 varieties of combs made, and the aggre- 

 gate number produced, of all these different sorts of combs, average 

 upwards of 1,200 gross weekly, or about 9,000,000 annually ; a quan- 

 tity that, if laid together lengthways, would extend about 700 miles. 

 The annual consumption of ox horns is about 730,000 ; the annual 

 consumption of hoofs amounts to 4,000,000 ; the consumption of tor- 

 toise shell and buffalo horn, although not so large, is correspondingly 

 valuable ; even the waste, composed of horn shavings and parings of 

 hoof, which from its nitrogenized composition, becomes a valuable 

 material in the manufacture of prussiate of potash, amounts to 350 

 tons in the year ; the broken combs in the various stages of manufac- 

 ture average 50 or GO gross in a week ; the very paper for packing 

 costs 83,000 a year. 



A hoof undergoes eleven distinct operations before it becomes a 

 finished comb. In this great comb factory, there are 456 men and 

 boys employed, and 164 women --in all 020 hands. 



