APPENDIX 477 



NOTE 9 (p. 147). 



Classification of the different forms of Hygroscopicity^ by Leo Errera 

 (Recueil de 1'Institut Botanique Le"o Errera, University de 

 Bruxelles, tome vi. 1906). 



A. PHYSICAL. 



(1) Condensation by cold surfaces, as of glass, metals, etc. 



(2) Condensation by capillarity, or capillary hygroscopicity : 



() where the water enters pre-existing capillary spaces, 

 as in the case of hair, wool, silk, cotton, wood- 

 shavings, etc., which is capillarity properly so-called j 



() where the water makes its own passage by pushing 

 aside the molecules or particles, as with gelatine, gum- 

 lac, powdered clay, agate, etc., an imbibition process. 



(3) Condensation by osmosis or osmotic hygroscopicity, where 



the substances affected are soluble in water and become 

 coated by a very thin pellicle of water, as with common 

 salt. 



B. CHEMICAL, of which examples occur in the behaviour of con- 



centrated sulphuric acid, absolute alcohol, quicklime, 

 chloride of zinc, chloride of lime, etc. 



NOTE 10, A (p. 266). 



On the loss of weight of ripe Gooseberries (Ribes Grossularia) when dried 

 in air at ordinary temperatures. 



THE average of two experiments which corresponded very closely 

 in their results may be thus stated : 



Weight of moist fruit taken as ... 100-0 



air-dried fruit . . . . 15-0 

 air-dried fruit after soaking two days 



in water to remove the sugars . 5-0 



The sugars in the air-dried fruit therefore weigh twice as much as 

 the combined skin, pulp, and seeds, and the relative quantities may be 

 thus stated for the entire berry : 



Water lost by drying in air . . .85-0 



Sugars ....... io-o 



Skin and pulp ...... 2'6 



Seeds 2-4 



lOO'O 



