On the Dry Rot 177* 



It is a well known fact, that the building of the Constitution 

 commenced when we were on the eve of a maritime war with 

 France, or it had already commenced, and therefore we may sup- 

 pose that the completion of the ship was hurried ; and that her 

 frame did not all arrive from the south in time, so that they were 

 compelled to employ the white oak in her construction : probably 

 the season in which it was cut was not much regarded, and there- 

 fore some of her white oak timber lasted forty years. 



I saw in one of the Reviews of the day a circumstance of this 

 kind, although I cannot now give the reference. In a mine, I 

 believe in one pi the German states, the timbers made use of to 

 support the roofs of the galleries, were in a few months destroyed 

 by the dry rot, and this could not be obviated by every experi- 

 ment that was tried, until they made use of the locust. The 

 effect WEis accounted for in this way : the dry rot, it is true, 

 destroyed the alburnum immediately ; but the decayed alburnum 

 answered for a coating to defend the heart- wood from its influ- 

 ence. If this be the fact, why did not the decayed alburnum of 

 the other timber answer the same purpose ? But however, if the 

 histories of those locusts were reverted to, it would most probably 

 be found that they were killed some time in the summer ; and it 

 will also be found that if the decayed alburnum be not removed 

 it will generate another disease, which in some respects resembles 

 and is very often taken for the dry rot. 



Numerous other instances can be brought to bear in this case. 

 Farmers cut their rails in the summer, when the bark will peel, 

 and they last from fifty to a hundred years. They account for 

 the fact in this way : if they cut them in the winter, the bark 

 will stick to the rails, and after a little while, the water gets under 

 it and causes them to decay sooner. On the contrary, they cut 

 their posts in the winter ; probably this is done for the convenience 

 of cutting holes in them at that season, and although their rails last 

 so long, yet their posts begin to decay in about seven or eight 

 years, according to the soil in which they are placed. When 

 from necessity they are obliged to cut a few posts in the summer, 

 (with the expectation however that they will soon decay,) if they 

 last thirty or forty years, (and there are instances of this kind,) 

 they speak of it as a very extraordinary circumstance, but never 

 inquire into the natural cause, nor alter their practice. There are 

 other instances of the extraordinary longevity of timber ; wooden 



Vol. XXXIV.— No. 1. 23 



