'2-i) r iiir( rsil 1/ of CdlifaniKt I'lihllcal Ions in liotaiuj | \ <ii.. 7 



1() one portion ;iloii<; witli till' |)oi'tioii to 1)(' yi'ouiid will decidedly 

 affect the nililiec content of the ^ronnd saiiiple since the j'lvater pai't 

 of the rnlilu'i' is contained in the e\ti-a-cainbial elements of the stem. 

 To test this niattei- \vc I'an a few analyses of ground matcTial from 

 both pofti(His of a nninbei- of |)lants. The results are o-iveii in the 

 following' tatth'. 



Tab[,e 2. — Vakiation in Rubber Content Due to Unequal Separation, Shown 



BY Analyses of Both Halves of Large 1'lants which had 



BEEN Split Lonoitudinally 



Date of Aeetone Benzene 



Cullortion Extract Extract 



Species Place of Collection 19IH Percent. Percent. 



4;") r. n. consimilis Adobe Valley, Calif. Sept. 19 ;i.70 2.55 



Adobe Valley, Calif. Sept. 19 :j.75 2.44* 



Adobe Valley, Calif. Sept. 19 :j.21 2.81 



457 (^. n. consimilis Gaspipe, Calif. Sept. 19 ;i.66 1.95 



Gaspipe, Calif. Sept. 19 2.97 2.07 



lt)7 C. u. viridulus North of Mono Lake, Calif. Sept. 22 3.71 1.74 



North of Mono Lake, Calif. Sept. 22 2 . 2S 2 . 47 

 *■ r)u])li<'ati' analysis. 



These figures imiicate that care must be exercised in splitting off 

 jxtitions of a plant for grinding- and analysis. As noted above it has 

 been almost uniformly our practice to cut u]) larger plants into trans- 

 verse sections and grind alternate pieces. 



For the first rough crusliing or grinding a small power di-iven 

 feed mill ])roved satisfactory. Tbc material was run thi'ongh this 

 inill a uiimbei' of times, the grinding phites being continually brought 

 neai'cr together until the maximum degree of fineness was attained. 

 At this stage practically all tlu> material could be passed through a 

 lO-inesh sieve. For the final grinding a hand-operated No. Enter- 

 l)rise coffee mill pi'oved successful. The final i-esult of this last 

 grinding was the |)r()(luction of material that would pass through a 

 24-mesh sieve. 



We have attem|)ted with some success to substitute the action of 

 a pebbh' mill for the greater part of tlu' final grinding.^' Since the 

 rubber is held within the walls of tlie individual cells and since, even 

 when put into solution by benzene, these confining walls must serve 

 to binder outward diffusion of the rubbei- to some extent, it seemed 



1" A niodifieatioii of a small Alihe pel)l)l(' mill (''siiij^lc sjKH-inun mill'') was 

 used. Mention mijiflit liere ho made of the fact that there are on the market a 

 nund>er of ])ower driven grinding machines which wonlil uiidouljtedlv ])erfonn an 

 iidtial reduction to 10-mosh nmcli more rapidly and i-veidy than the apparatus 

 descrilii'il almve. 



