Taken for analysis, frSiG grains. 



6-326 grains gave 9-01 grains CO^ and 

 4-30 grains H^O. 



CO, = 9-01 =2-457 C = 38-84 



H,O = 4-30 = -478 H= 7-556 



Oxygen, by difference = 3-391 = 53-604 



= 3237 C 

 • = 7556 H 

 ' = 3350 O 



6-326 100-000 

 From these figures we may consider the formula to 

 C„H,.,0„. 



analysis, and determinations of melting 

 cl-c, there is no doubt that the substa 



From this 



be 



point, 



crystalline form, 

 mannite. 



A second combustion of the mannite was made, the figures 

 obtained confirming the previous result. They are given here : — 

 6-345 grains were taken for analysis. 

 6-345 grains gave 9-11 grains COj,, and 

 4-316 grains H^O. 

 CO =9-110 ■ =2-485 = 39-16 % = 326 C 



H,0 = 4-316 = -479 H= 7-55% = 755H 



Oxygen, by difference = 3-381 = 53-29 % = 333 O 



6-345 100-00 % 

 = g H J , O g (mannite). 



MISCELLANEOUS. 



The manna contains — 



3-5 per cent of moisture, 

 1-1 " ash, 



a portion of which was dirt, as the manna is somewhat impure, 

 as already stated. 



The manna contains no tannic acid ; its contact with the bark 

 and dark colour might lead one to expect at least a trace. 



It only ferments in the sliglitest degree after two days' treat- 

 ment with yeast. 



QUANTITATIVE ANALYSIS OF THE MANNA (sUMMARy). 



The manna was dissolved in water, filtered, alcohol and lead- 

 acetate added, which precipitated a small portion of the sub- 

 stances in solution. After removing the lead by sulphuretted 

 hydrogen, and evaporating to dryness, the residue was treated 

 with boiling 90 per cent, alcohol ; this was dried and weighed. 

 In this way 89-65 per cent, of mannite was found. 



We may therefore conclude that picked samples of the manna 

 from Myoporum platycarpum contain from 85 to 90 per cent, of 

 mannite. 



