40 
Indian Forest Records. 
‘-wov xiccurus. [Yol. YI 
(in) Report from Bombay received through the Director of Industries 
Secretariat , Bombay. 
Greaves Cotton & Co. write that so far they estimate the value of the gum at 
toTe finer simple ** ° Wt ' ^ d0Wn “ Bomha ^ 1 ™<>erstand this to refer 
4. Under-extracted Gum. 
Gum in which about 30-40 per cent of resin is allowed to remain 
unextracted has been tried as a paper size. From the reports received 
it is evident that this gum, dissolved in caustic soda, gives a fairly 
satisfactory size, though the exact process of preparing this size either 
rom the resin direct or from the mixture of rosin and gum still remains 
to be finally worked out. 
(i) Note on the use of Under-extracted Gum, by Mr. W. Raitt, Cellulose 
Expert. 
as fl e ;:t Pa3te haS a “ approximate ®°“P°sition according to Mr. Puran Singh 
Resin 
Gum 
Moisture 
Sand and refuse 
40 
45 
10 
5 
The rosin a almost wholly non-saponifiable and therefore differs widely in 
character from the pine rosin commonly used for paper-sizing. In practice 
however, a large amount of the latter is purposely left in the “ free ” or uncom 
brned condition in the size, and it is considered that a pine rosin size containing 
a “ ‘ d ® raUe a “° unt , m the free sto te gives better sizing effects than a fully 
* .There ore, as practically the whole of the resin in this waste goel 
into solution as free resin it should prove a good sizing agent. The gum flso 
emg w oily insoluble in water, should likewise have a sizing effect provided it 
can be precipitated from solution and apparently this can be done. 
oth resin and gum go into perfect solution with 3 per cent. NaHO (i.e 100 
resrn waste+ 3 Na H °+ water sufficient to give the deified density) TW are 
not fully soluble in soda carbonat^ so caustic soda must be used but the amount 
wire'cloth* filter tlt t ^ S ° lu , tioi \ can then be Passed through a flannel or fine 
Uitated h i k ® out ® and and extraneous matter. It can then be preci¬ 
pitated on the pulp or paper by adding alum to the extent of 4 per cent, on original 
mfikv wlit r e eSm "T; B °n h f Si “ and gU “ are of solution as aTe 
fibrts h t precipitate, and the coagulating effect of the alum fixes them on the 
treats? 6 ! \ er ! With are S f eral strips o£ unsized filter P a Per which have been 
treated by first dippmg in the solution and then in the alum. A comparison of 
is lonsMerablf TIT'* 1 p ° rtions of the stri P s will show that the sizing effect 
or warn of , m ] r6gard SUCh resuIts as eonelusive as we are unable 
for want of suitable plant, to reproduce all the conditions of a paper-mill wher e 
[ 342 ] 
