OLEOEESIN PRODUCTION. 35 



Some of these are illustrated in Plate I, figures 3, 5, and 6, and Plate 

 VII, figure 2. They present various advantages and disadvantages. 

 The earthen or clay cups do not rust and discolor the gum as the 

 metal cups that have been used for some time may do, but they 

 are subject to breakage in handling and during freezing weather. 

 Various efforts such as lining metal cups with wood have been made. 

 One of the most successful has been coating old cups with bakelite, 

 which prevents the discoloration of the gum. The argument that 

 the metal cup becomes hotter during warm weather and causes greater 

 evaporation of the gum is advanced by clay-cup advocates. Partly 

 covered cups which reduce evaporation are used in India. 



The connection between the cup and the surface of the tree is made 

 by the use of gutters or aprons. (PI. I, figs. 3 and 6, and PI. IV, 

 figs 1 and 3.) Efforts have also been made to develop an apronless 

 cup. In order to attach the cups and gutters to the trees, nails are 

 often employed, but these are very undesirable from the point of 

 view of the sawmill end of the operation, for even though they are 

 theoretically all removed, headless or hidden nails may occur and be 

 very destructive if encountered during the process of sawing up the 

 timber. "With this in mind, wooden pegs (PI. IV, figs. 3, 4, and 

 6) to support the cups or soft lead nails to attach the apron, when 

 the cup is raised, are used by some operators so as to avert possible 

 damage if accidentally left in the tree. 



CHIPPING. 



Two sizes of hacks are illustrated in Plate IV, figure 2. The hack 

 with the narrow opening or " bill " is a " 00," such as was used on 

 the narrow chipping at Columbia, Miss. The other hack is a " No. 

 2," such as was used on the standard operation by the cooperating 

 company. The method of chipping, a free arm stroke, is illustrated 

 in Plate IV, figure 4. It would be very desirable if a gauged hack 

 could be devised which would mechanically govern the size of the 

 chip cut. The "puller" for cutting a streak on the higher faces is 

 illustrated in Plate IV, figure 6. It is said that "pulling" is more 

 difficult than chipping 33 ; the use of the 00 hack and narrow chipping 

 defers the time when pulling need be used. With the puller good 

 narrow chipping may be obtained, as in the case of the double chip- 

 ping :it Columbia in 1017. It is thought to be highly desirable to 

 ii-'" a sharp tool arid to make clean smooth cuts at regular intervals.' 

 Practically, chipping once in seven days has been found to give- 

 satisfactory results. The Columbia, Miss., experiments indicated 

 that chipping twice a week was not desirable for long opera! ions. 



i <.r. Berv. I'.ui. 00, \>. 19. 

 ••In India the smoothness <>r the face ot channel in especially emphasised. The great- 

 tit care Ih taken to remove rough surfaces which would promote the formation "i scrape. 



