188 TRACTS ON VARIOUS SUBJECTS, &c. 



lands are high ; and particularly if the object should be, throui^h 

 their means to reduce those prices. 



Your observations on the attraction of moisture and rain, 

 appear to be judicious. Trees have usually been recommended 

 for that purpose. 1 am of opinion, however, that cultivation has 

 also a tendency to produce the same etlect ; and in proportion to 

 the extension of arable fields, so will be the increase of moisture. 

 This will readily be conceived by attention to the following facts. 



On the 5th of May last, I cut down a square rod of barley 

 wheat, that had been two months in the ground, from the time 

 of sowing. The produce in a green state, was 146 pounds, or 

 about 10^ tons per acre. Jt was carefully collected and dried in 

 the air, nntil the 26th of May, when it weighed no more than 46 

 pounds ; consequently, 100 pounds of moisture had been evapo- 

 rated ; and if only half this weight be supposed to have been, at 

 the time of cutting, absorbed in the soil and roots, under the 

 thick shade of an exuberant crop, the total quantity of moisture 

 would be 150 pounds on a square rod, or above ten tons upon an 

 acre. These circumstances lead me to believe there is a more 

 accurate mode of determining the comparative moisture, on 

 ploughed and unploughed lands, than by the vapour glasses 

 lately introduced in Engfland. 



As the planting of trees, for useful timber and fuel, is an im- 

 portant object here, I have always intended it should keep pace 

 with cultivation. During the last four years several thousand 

 pineasters and oaks have been set out, and there are still a good 

 many in the nurseries. This year the nurseries are to be estab- 

 lished on a larger scale. Every cone from the pineaster and 

 cypress trees at Plantation-house has been collected, as well as 

 the seeds of the Botany Bay willow. These trees, and the indi- 

 genous red wood, together with the largest species of Morgossa 



