IN CROPS AND MANURE. 36 



general masses reduced to powder that samples were taken for ulti- 

 mate analysis, before proceeding to which, they were carefully dried 

 in vacuo at 230° F. 



It is not likely that any accurate mean result should have been 

 come to from^ an examination of the produce of a single season. I 

 should even say that the year in which these inquiries were under- 

 taken was little favorable to them, inasmuch as the crops were gen- 

 erally bad ; but it is obvious that they form a nucleus, around or by 

 the side of which the results of other seasons may be arranged, and 

 an average from larger premises come to. 



POTATO TOPS OR HAUM. 



A piece of land measuring 120 square yards, marked off from a 

 spot that had suffered from drought, yielded 47.0 lbs. of green tops, 

 which were reduced by drying to 18.4 lbs. A similar extent of 

 surface, selected from a part of the field that looked well, gave green 

 tops 79 lbs., which dried in the air were reduced to 16 lbs. We 

 should thus have 23^ cwts. of green, and 6j cwts. of dry tops per 

 acre. The crop of potatoes in 1839 yielded at the rate of 101^ 

 cwts. per acre. One hundred grammes, or 3 oz. 4 dwts. 8 grs. 

 troy, of the top dried in the air, lost 12 grammes, or 7 dwts. 17 grs. 

 by thorough drying at 230° F. The weight of the tops yielded per 

 acre, taken as dry, consequently amounts to 5 cwts. 2 qrs. 14 lbs., 

 and by elementary analysis they were found to have the following 

 composition : 



Carbon 44-8 



Hydrogen 5.1 



Oxygen 30.5 



Azote 2.3 



Salts and earths 17.8 



100.0 

 LEAVES OF FIELD-BEET, OR MANGEL-WURZEL. 



Upon a surface of 500 square yards, 976 lbs. of leaves were gath- 

 ered, the weight being taken two days after the roots were pulled up. 



55 lbs. of leaves reducible to powder by drying in an oven, were 

 brought to 6.6 lbs. 



3 oz. 4 dwts. of leaves dried and pulverized, lost by desiccation 

 at 230" F. 3| dwts. of moisture. The 6.6 lbs. brought to that state 

 of dryness would have weighed 6.1 lbs. With these data it is found 

 that the 976 lbs. of green leaves gathered upon 500 square yards 

 would have weighed when dry 108.9 lbs. ; and that the acre produced 

 85| cwts. of green and 9| cwts, of dry leaves. The crop of roots 

 which answers to that quantity of leaves, was in 1839 but 6 tons, 2 

 cwts., that is to say, little more than half a crop ; for our average 

 is about 10| tons. 



COMPOSITION OF DRY LEAVES. 



Carbon 38.1 



Hydrogen 5.1 



Oxygen 30.8 



Azote 4.5 



Salts and earths 21.5 



100. 

 31 



