330 



Mr. Randall on iJie 



whicli is formed on every part of the 

 deeajing wood. Its ajipcarance often 

 varies, depending almost entirely on the 

 sitnalion in wliich it is cngcHdcrcd. 

 That fnngi which is most commonly 

 found is ilcshy to the touch, adheres 

 firmly to the wood, walls, and every 

 contiguous sul)stanie, and branches out 

 iiilo apparently strong fil>rous loots. It 

 occasions a gradual decomposition of 

 the wood, begitming at the surface, and 

 finally proceeding through the whole 

 mass. If any portion, however, remain 

 exposed to the atmosphere, the destroy- 

 ing principle of the limgus is arrested. 

 UcJice, floors and other wooden work 

 (reqiiently appear perfect to the eye, 

 when nothing but its surface is left nn- 

 destroyed. Wood-work, which is painted 

 Qji one of its sides, is wholly decom- 

 posed ; the paint preventing the sponta- 

 neous oxydation of its surface. All 

 wood exposed to the light and air un- 

 dergoes a slow coud)»stion, (if not pre- 

 vented by being covered over Mith 

 paint, &c.) This arises from the burn- 

 ing of its escaping hydrogen by the 

 oxjgen of the alniosi)licre, and whicli 

 gives it a brown ct>lour. A chapel, 

 near Grosvenor-sqnaie, was found in a 

 rapid state of decay, arising from this 

 rot. On a removal of the boards which 

 composed tlie flooring under the pews, 

 tin: whole exhibited a complete area of 

 fungi, the wood of which remaining only 

 in the condition of fragments. It emit- 

 led a strong odorous scent, which so 

 jiiiich afl'ected the workmen emjtloyed 

 ia clearing it away, that they became 

 faint, complained of head-ache, with 

 jiainful respiration, and were finally 

 foiccd to dLscoiitiiiue tlieir labour. A|)- 

 proachiug the spot, I nnsclfcxj)ericiieed 

 similar sensations; upon letting fall some 

 lighted .shavings, the combustion in- 

 stantly ceased. A lighted candle, liav ing 

 been forced into the void under tlie 

 floor, was sooncNliiiguished; and upon 

 following it with the hand a consider- 

 able heat was felt; i)arlicles of water 

 vcro perceived upon the surface of the 

 siinoundiiig wood. As these effects 

 oiulonbledly proceeded from a slate of 

 feriiientalion, and from the .ur.gns being 

 fe.rnicd only on those i>arts wliicli were 

 immediateiy in that state, it is evident, 

 thai, if in the construction of buildings 

 fermentation coidd be prevented from 

 taking place, fungi would not be formed 

 nm the dry-rot apj^ear. Taking, then, 

 tJiat this rot arises from a previous slate 

 «t fermeidatiun, 1 «oucludo, tliat tliu 



Cure of Dry Rot. [Nor. I, 



liberated frases are the essential matcriala 

 from which the genuination and fecun- 

 dation of the fungus-plant is produced^ 

 as it is formed only when circumstances 

 haTC combined to produce this pheno- 

 menon. I'his chapel was completely 

 repaired, adopting the mode explained 

 in my former letter; it has now been' 

 finished more than five years, and is 

 perfectly free from any appearance of 

 fungi, or dry-rot. 



The fungus-plant having destroyed all 

 the wooden work which was upoii the 

 walls surrounding the inside of th« 

 chapel, which, on its restoration, was 

 found not of suflicieut substance to ad- 

 mit of oxydating by scorching with a 

 common fire ; the sulphuric acid was 

 had recourse to for the purpose; this 

 may be ])urcha.sed at any chemical 

 depot, and is about five or six shillings 

 a-quart, wine measure. It may be di- 

 luted with one-third of w aler, and put 

 on the surface of the wood with a flat 

 hog-hair brush. Tf the surface to hei 

 oxydatcd be slightly planed over, it will 

 create a great saving in the use of thw 

 xcid, as it will allow of its acting mors 

 powerfully on the wood than it other- 

 wise would do. Its rough surface, when 

 left from the saw, prevents the action 

 of the acid without a useless waste of it, 

 for which this little additional labour 

 will not be found to be an equivalent. 

 The exjiencc of oxydation, by means of 

 sulphuric acid, if done by a careful 

 man, will not exceed a halfpenny per 

 foot superficial ; and the additional 

 painting over with the solution of the 

 siiljihate of iion, will not, as before 

 stated, exceed a fraction for the same 

 measure; hcue, tlie cost is butlrifiing, 

 whether the oxvdafiou is done by fire 

 or a(;id. Eut no other than the acid 

 Diode will be found to answer the pur- 

 pose for slight vvocd-wtiik, as the vio- 

 leiici' of fire warps it so much, as to 

 reiidoi it unfit for its intended purpose. 

 The indcstructiliilily given to wood, by 

 this opcialion, arises from its absorption 

 of oxvgen. in which slate it will resist 

 the combined action of sun, air, luois- 

 tiire, and fungi, for an almost endless 

 time; and tlitie cannot exist a doubt, 

 that, if the oxydation be jnopcrly aji- 

 piied to the rot in wood, however an- 

 ticipated or expected, that it may be 

 entirely inevcntcd. In the charring, or 

 oxydatirtii by the acid process, what 

 renders it of more importance in jirac- 

 tice is, that it may be used for timbers 

 that ate alieadj iu a buUdiiig. Consi- 



