148 TRACTS ON VARIOUS SUBJECTS, &c. 



less than in England ; owing to the almost unceasing powers of 

 vegetation which are observable in this climate. It is probably 

 from this cause, that the gooseberry, the currant, and some other 

 shrubs become evergreens, and bear no fruit. If then, in these, 

 we observe so great a change in the process of nature, it is at least 

 probable that similar changes may take place, although not per- 

 ceptibly, in other vegetable productions. 



I have not yet completed my experiments upon the effect of 

 cutting potatoe haulm : but so confident of success do I feel, from 

 the observations I have already made, that I mean to adopt the 

 practice upon a crop of two acres allotted expressly for the pur- 

 pose. My former trials were indeed imperfect, on account of 

 cutting the haulm within a field of potatoes, so that when the 

 uncut haulm was attacked and devoured, the caterpillars naturally 

 crawled to the young and tender sproutings of the cut haulm, and 

 eat them off as fast as they appeared. 



That the cut haulm will reproduce leaves I have frequently 

 ascertained. The following are some notices I have retained of a 

 small experiment : but, the comparative produce of potatoes from 

 the uncut and cut haulm was accidentally omitted. 



On the 12th of February, 1809, the potatoes were planted. On 

 the 4th of April, whilst in blossom, a square rod was mowed. It 

 yielded 67^ pounds of fine tender haulm, which is at the rate of 

 10,800 pounds, or 4| tons per acre. The haulm of the adjoining 

 crop was left uncut. I observed on the 28th of April, the uncut 

 haulm had become brownish, and was much eaten by caterpillars, 

 whilst the haulm that was cut, (having reproduced leaves) was of 

 a fine green. The last notice I took of this experiment was on 

 the 14th of May, when the cut continued in green leaf, that is, 

 40 days after it had been mowed. This is sufhcient to prove that 

 the powers of vegetation do continue in this climate long after 



