LECTURES AND ESSAYS READ AT INSTITUTES. 337 



It will be seen that the Schumacher is about five days in advance of the 

 Clawson ; that the growth of each kind proceeds by a somewhat uneven pro- 

 gression, the increase of growth bearing some relation to the preceding daily 

 temperature, because the specimens were gathered in the morning. 



The falling off in the seventh cutting of Clawson is curious, and I can offer 

 no explanation. After the complete ripening of the grain there is a sensible 

 decrease, showing that the con'^mon impression among farmers that there is 

 diminished production of grain when harvesting is delayed too long, is well 

 founded. This loss is not from careless handling of the grain or from drying 

 by over-ripening. The loss is a real one, thongh not large. 



CHEMICAL ANALYSIS. 



The wheat was powdered by prolonged beating in an iron mortar, and sifting 

 this in a wire sieve of 38 meshes to the inch, and this process repeated till the 

 entire quantity taken had passed through the sieve. The amount of water in 

 each specimen was determined by prolonged heating in the steam bath and 

 cooling in a sulphuric acid desiccator till there was no further loss of weights, 

 and the entire loss of weight was taken as water. The results of all analyses 

 and other estimations are based upon water-free material. 



The ash was determined by prolonged burning in a shallow platinum dish, 

 kept at a low red heat till the ash burned white, and the ash was weighed with 

 its natural contents of carbonic acid. The percentage of ash is given in Table 

 I, which shows a regular decline as the grain develops by formation of ash-free 

 carbhydrates. 



The cellulose was estimated by boiling in water containing 1^ per cent 

 sulphuric acid, then with water and repeating process ; then with I^ per cent 

 caustic potash solution — then boiling with water and washing the crude 

 cellulose with alcohol and ether, following Hennebergh's method. The crude 

 cellulose was then dried in water bath to constant weight ; then incinerated 

 and the weight of ash deducted, when the residual weight was taken as 

 cellulose. No estimate was made of the small amount of nitrogen which it 

 contained. The cellulose was of a light brown color. 



The percentage of cellulose regularly decreased from the earliest formation 

 of the grain up to the time of ripening, the amount being greater in the first 

 cuttings of Clawson than in those of Schumacher, because of its more 

 immature condition. After ripening there is an increase of cellulose, showing 

 that over-ripening is attended by a loss of nutritive material, if we consider 

 dense cellulose as indigestible. The increase of cellulose seems to be in inti- 

 mate relation to the process of hardening exhibited in dead ripening. 



The nitrogen was determined in the usual way by combustion with soda- 

 lime, and the amount of albuminoids estimated by multiplying the nitrogen 

 by 6.4. The percentage of nitrogen is given in Table I, and the estimated 

 amount of albuminoids in the dry substance is given in Table II. 



