and other valuable Timber Trees. 389 



position and dense mass of timbers that are seen in the hull 

 of a battle-ship of the line on the stocks is considered as favor- 

 able to this action, although there are no doubts but what the 

 germs of the disease are lurking in the timbers previous to 

 their use, occasioned by the want of care and suitable selec- 

 tion of appropriate trees, and preservation of the timber after 

 cutting. The local sites of navy yards, where there must be 

 a proper depth of water, unavoidably place the timber in a 

 topographical situation that is unfavorable to the preserva- 

 tion of the wood, as heat and moisture accelerate the chem- 

 ical action, and promote the fungous growths, whose nu- 

 trition depends on the chemical changes heretofore men- 

 tioned. 



Could we always find a suitable hydrographical station for 

 a navy ^^ard, where, combined with its facilities, there was 

 a dryness and purity of atmosphere, many of the causes 

 that decompose the materials tor ship-building would be pre- 

 vented ; but, as such localities cannot always be found in the 

 surveys for such stations, we must patiently submit to the in- 

 jurious effects of heat and damp almosphere, however well 

 giiarded the ships may be in their sheltered positions by ven- 

 tilation and suitable protection ; although it is of the highest 

 importance that the geographical situations of such places 

 should be well understood and taken into consideration, 

 as rivers, marshes, bogs, mean standard of the thermom- 

 eter, barometer, and hygrometer, and mean quantity of 

 rain. 



The proper season for cutting such timber will next be con- 

 sidered. The months of July and August, when the trees arc 

 in foliage, and the juices circulating freely, is decidedly the 

 best period for cutting; as then the greater portion of the al- 

 bumen is contained in the cambium or descending sap, while 

 most of the nitrogen is set free by exhalation, and is princi- 

 pally combined with the fluids that circulate exteriorly. T he 

 trees, after they are fallen, should be immediately rough hewn, 

 and deprived of their sap-wood and bark, placing the timber 

 in the most favorable situation for seasoning and desiccation 

 by elevating it from the earth. The ordinary process of sea- 

 soning wood consists in merely exposing it to a current of air. 

 It would be a desirable thing if we could find a location where 

 35* 



