82 



Moisture. — With the exception of the Fameuse, the pei'centage of water in all 

 the specimens taken 25th May lies between 10-94 and 72-11 — practicallj', between 71 

 and 72. The Fameuse is more succulent, and contains 75-45 per cent, water. In 

 the leaves gathered 20th September we find a general diminution in the percentage 

 of water, the loss being in the neighbourhood of 12 per cent. It is interesting, and 

 perhaps instructive, to note that with regard to the amount of water, the leaves of 

 25th May fall into the same order with those of 20th September, the Duchess of 

 Oldenburgh containing least and the Fameuse most M-ater, showing clearly that 

 while all have follovved the general law in loss of moisture each has retained its 

 own characteristic individuality. 



Average percentage of water in young leaf j. 72-36 



do do matarer leaf 60-71 



Organic Matter. — This includes all the combustible material of the leaf, and is 

 composed of carbon, oxygen, hydrogen and nitrogen. In the leaves of 25th May, 

 those of the Duchess of Oldenburgh and of the Wealthy, the percentages of organic 

 matter are almost the same and head the list. The Tetofsky and Northern Spy also 

 contain almost identical amounts, or somewhat less, than the |.wo first mentioned, 

 while the Fameuse contains the smallest quantity of organic matter. This order is 

 preserved in the leaves plucked 20th September. From an inspection of these two 

 colnmns it will be observed that there is a general diminution of water and increase 

 of organic matter as the season advances, and that any special variety preserves its 

 relative position to other varieties in this respect throughout the season. 



Average percentage of oi-ganic matter in young leaf 25-31 



do do maturer leaf 35-83 



Ash — The percentage of all the inorganic or mineral constituents of the leaf 

 are found in this column. With the exception of the " Wealthy " we find the 

 amounts of ash of the loaves of 25th May closely approximating one another. The 

 leaves of the Wealthy fall about, 5 per cent, below the others in ash constituents. In 

 those of the 20th September we find a general increase in the percentage of ash, 

 amounting from, 5 to 1-5 per cent, over those of 25th May. 



Average percentage of ash in young leaf 2-33 



do do maturer leaf. 3-46 



Phosphoric Acid — With regard to the composition of the ash as detailed in the 

 columns following it is difficult to discover in many cases what principle, if any, 

 underlies the distribution of the mineral constituents throughout the tissues of the 

 leaf during its growth. Without reading too much, however, into the results of a single 

 analysis, an inspection of this column shows most clearly that the young leaf con- 

 tains in its ash a much larger percentage of phosphoric acid than the maturer one — 

 in some instances the phosphoric acid in the latter is but one-half, or even less, than 

 that of the younger leaf This would lead us to suppose that as the season 

 advanced there was a retrograde movement of the phosphoiic acid of the leaf to 

 other parts of the tree. As the seed is well known to contain a i-elatively large 

 quantity of this acid we may legitimately be allowed to think that the food 

 elaborated in the leaf found its way finally, in part, at all events, to the fruit and 

 other portions of the tree. And this undoubtedly expresses a truth (though pro- 

 bably not the whole truth), for we observe that the average number of pounds of 

 phosphoric acid per 1,000 pounds of the younger leaf is higher than the cori-espond- 

 ing number for the maturer leaf, viz. : as 2.45, 1.94, and this in spite of the fact that 

 the percentage of ash in the latter is considerably higher than in the former. 

 Average percentage of phosphoric acid in thoj-oung leaf 10-47 

 do do do maturer leaf 5-82 



Potash — It would n6t be safe fro n the results tabulated to advance stronirly 

 any theories regarding the disposition of this important element in the leaf. The 

 percentage of potash in the young leaf is somewhat lower than that in the maturer 

 leaf. When we, however, consider the increased amount of ash in the latter we find 

 that per 1,000 pounds the older leaves contains 1-5 pounds moi-e potash than the 



