438 



Pine Plants in Soil at Castle Semple^ 



I have written Mr. Lauder my views of the treatment of 

 the plants, in order to the proving of them regularly in the 

 ensuing spring ; and, should he be as successful in this case 

 as in growing the plants, I shall endeavour to send you a spe- 

 cimen of the fruit, which, I think, Major Harvey will not 

 refuse me. I intended to have asked him before I wrote you, 

 but, he having sent me notice to pack the fruit accompanying 

 this, as it must be sent off to-morrow, I had not an oppor- 

 tunity of seeing him. 



I give you the following extract from Mr. Lauder's letter, 

 as a final answer to your query to Mr. Neill, about the best 

 substance for plunging pots of pines in, in steam-pits : — " I 

 found the thermometer, in the bed of soil, generally 2°, and 

 sometimes 3°, higher than one plunged at the same depth 

 among rotten leaves ; and 4°, and sometimes 5°, higher than 

 one plunged at the same depth among gravel, all in the steam- 

 pit. The heat was frequently in summer as under : — 



92° 



Soil 



_ 



- 93° 



90 



Leaves 



- 



■ - 90 



87 



Gravel 



- 



- 88 



"Soil - 



Leaves 



Gravel 



"When the steam was withheld longer than, usual, the- 

 thermometer among the gravel was the first that got lowest \ 

 but, on the other hand, when the steam was applied longer 

 than usual to the pit, the gravel was soonest heated. Since 

 my return from Edinburgh, I withheld the steam from the pit' 

 for several days, until the thermometer plunged to the same 

 depth ranged as follows, on the morning of the 6th of Jan. : — 



" In the bed of soil 

 Among the rotten leaves 

 Among the gravel 



80° 

 79 



74 



" On the above day, I let the steam into the pit for about 

 four hours, and the thermometer ranged, the three following 

 days, without any more steam, as follows : — 



fSoil - 83° 



On the 7th \ Leaves 82 



[Gravel 90 



f Soil - 85° 

 8th -1 Leaves 83 

 [ Gravel 88 



[Soil - 85° 

 9th \ Leaves 83 

 [Gravel 80" 



It appears, from the last trial, that Mr. Lauder has stopped 

 too soon from making his observations : he ought to have con- 

 tinued them until the heat in the bed of soil, as indicated by 

 the thermometer, had sunk lower than 85°. This, however, 

 is the degree of heat at 1 ft. deep in the earth, during sum- 

 mer, in Grenada, as a gentleman, a planter there, wrote home 

 for my information. The thermometer in the steam-pit was 

 plunged 9 in. deep. From the above trials, I think it evident 



