IN CROPS AND MANURE. 36 



general masses reduced to powder (hat samples were taken for ulti- 

 mate analysis, before proceeding to which, the)^ 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 Vv'ere reduced to 16 lbs. We 

 should thus have 23| cwts. of green, and Q\ 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 

 hrought 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 9j 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. 



GOMPPSITION OF DRY LEAVES. 



Carbon 38.1 



Hydrogen 5-1 



Oxygen 30.8 



Azote 4.5 



Salts and earths 21.5 



100.0 

 31 



