21() I' iiii'i rsil 11 of Calif oniiii I'tihlicdl l(His in liotdtiii |\'ii,. 



h. (IIK.MICAL ANALYSIS 



Tlic (>ri<iiiiiil clKMiiical aiuilysis ot" CJirnsofluiin n us was nijulc in 

 Oetolx'i'. IfH)."), liy Profcssoi- (i. K. ('olhy of tlu' ( ';ilif()riii;i ^^xpci-iinciit 

 Station. Al llir st;ir1 of onr investigations in l!tl7 ;i few inuilyscs 

 were very kindly made lor us by i*i-of('SSor P. I>. llililiartl of llic sauH' 

 station. Tlic gvi-ni majoi-ity of tlie analyses listed in ilie various tables 

 wbieli follow were inad<' under ibe dii'i'dion of tlie junioi- autbor, in 

 wbose biboratoi-y Ibe iieeessary gi-inding and extraction apparatus was 

 set u|). 



Tbe i)ai"liLMdai' iiietbod of ebeinieal aual\sis wbieb we ba\'e almost 

 oxeliisively em))loy(Hl consists in tbe tborouoii exti'aetion of a finely 

 ground sani))b' of nudei'ial. first wilb acetone and second witli benzene. 

 'I'be acetone e.xti'act is taken to contain approximately all resins, fats, 

 and sindlar bodies; tbe benzene exti'act to contain tbe I'ubbei'. A de- 

 tailed scbedule of tlic wliole proccss is giveu below for tbe convenience 

 and assistance of those wlio may care to make use of this method or 

 some improvement upon it. It is to be understood that the ])eriods of 

 extraction as well as the length of the periods of di-ying to constant 

 weight were definitely determined after a large numbei- of ])reliminai'y 

 efforts. The few early extractions were made with one of the numerous 

 modifications of the Soxhlet apparatus, while for tbe great majority 

 the Bailey-Walker extractor was employed. Tbe acetoiu^ extraction 

 was made over the water-bath, tbe benzene extraction on electi'ic hot 

 plates. The method may be sunnnarizi d as follows: 



(1) Five-gi'am sample extracted .'! bours. boiling acetone. 



(2) Acetone flask dried S hours, cooled in desiccator and weigln d. 

 (8) ^laterial in cxti-action tbiiuble or sipbon tube dried, placed in 



a second flask, and subjected to action of boiling benzene 

 for '.-> bours. 

 (-1-) Flask containing benzene extract di'ied 4 bours. coob d in 

 desiccatoi". and weigbed. 



Two layei's of filler papei- were placed at the liottom of tbe siphon 

 tube, as well as a plug of cotton. So complete a [)roteetion was this ar- 

 raiigement against the coming o\'er of partiides of tbe sample that fil- 

 tration of th(^ solution at the completion of the exti'act ion was iu)t nec- 

 essary. Similarly, a plug of cotton placed upon tbe top of tbe ma- 

 tei'ial in tln' sipbon tube obviated ;iii\- dangei' of an o\-ertlowing of 



