344 ANNUAL RECORD OF SCIENCE AND INDUSTRY. 



in cases where the heating or cooling slowly to the same de- 

 gree would not produce a similar effect. Inquiries into the 

 influence of temperature upon the rapidity of germination 

 confirm the results already obtained by Mr. Sachs that for 

 each species there is a most favorable degree of temperature 

 for growth, since growth takes place at that point more rap- 

 idly than at any other temperature ; and that below this 

 point the length of a growing radicle increases in proportion 

 as the temperature is elevated, while above that it is dimin- 

 ished more and more as the temperature ascends. 1 E, Part 

 K, 1870,386. 



CHANGES IN THE PROXIMATE PRINCIPLES OF HERBACEOUS 



VEGETABLES. 



Deherain maintains that the proximate principles of vege- 

 tables migrate from the older to the newly formed leaves, 

 and that this migration is associated with a transformation 

 of glucose into cane-sugar, while, when the seed is formed, 

 the cane-sucrar is converted into starch and the albumen into 

 gluten, both insoluble. In this way the conversion of solu- 

 ble into insoluble principles and the accumulation of sub- 

 stances in the seed is accounted for, and is illustrated by the 

 following experiment: If a porous vessel containing distilled 

 water be placed in another vessel containing a solution of 

 cupric sulphate, the salt penetrates by diffusion into the in- 

 ner vessel. If then a few drops of baryta water be added to 

 the inner vessel, the salt is precipitated, the equilibrium is 

 disturbed, and a new portion of cupric sulphate diffuses into 

 the inner vessel. The salt may be again precipitated by the 

 baryta water, and the operations repeated till eventually the 

 whole of the cupric sulphate will have passed into the porous 

 vessel, and there become precipitated. 21 A, IX.,e7wZy, 1871, 

 577. ' 



EXTRACTION OF AMMONIA FROM THE ATMOSPHERE BY HUMUS. 



In the course of certain experiments made by Bretschnei- 

 der upon the extraction of ammonia from the atmosphere by 

 humus substances, he came to the conclusion that the anitro- 

 genous, brown, organic combinations which are obtained by 

 boiling a solution of sugar with dilute sulphuric acid have 

 the property, when moist, of extracting ammonia, in a dry 



