30 HENRY G. SMITH. 



ground to a fine powder, so that extraction should be 

 practically complete. 



The calcium oxalate. 



The crystals which were removed from the surface of 

 the water were almost white, and in appearance an im- 

 palpable powder. 0*1279 gram of air dried crystals suffered 

 no loss when heated for two hours at 100-110° 0., but 

 when heated to constant weight at 170-180° O., they lost 

 0*0149 gram, equal to ll'Gof; 0.0«Oa + H a O contains 12*33°/» 

 water; on igniting and fully carbonating the residue the 

 calcium carbonate formed was 0*0835 gram. This shows 

 that only one molecule of water was present, because with 

 two molecules only 0*0779 gram could theoretically be 

 obtained, and by the method of collecting, the crystals 

 could not have been quite pure. No magnesia was detected. 



The calcium oxalate was determined quantitatively in 

 4 grams of bark, ground as fine as possible. The barks 

 were boiled with dilute hydrochloric acid, the filtrate made 

 alkaline with ammonia and then acid with acetic acid. The 

 precipitate was determined as calcium carbonate in the 

 usual way. Volumetric determination with permanganate 

 was not satisfactory. 



The percentage amounts of calcium oxalate (0 2 O 4 Ca -f 

 H 2 0) in the anhydrous barks of the several species was as 

 follows. They are calculated from the calcium carbonate 

 found. It is assumed that the whole of the calcium oxalate 

 existed in the crystallised condition, the form and appear- 

 ance of which can be seen from the micro-photograph 

 attached, for which I am indebted to Mr. J. W. Tremain 

 of the Technical College. 



Following are the percentages of calcium oxalate : — 

 Eucalyptus gracilis 16*66, E. Behrlana 16*50, E. salubris, 

 16*00, E. oleosa, 10*64, E. dumosa 9*80, E. salmonophloia 



