THE BLUEING OF CONIFEROUS TIMBER. QI 



1,250,000. The four specimens from Strathdon had a limit 

 of elasticity of 3042 lbs per sq. inch, and a modulus of elasticity 

 of 1,05 1,000. 



"Now, really good Scots pine should have an elastic limit — 

 and this was obtained in other material free from the fungus — 

 of from 4000 to 6000 lbs. per sq. inch, and a modulus of 

 elasticity of anything from 1,500,000 to nearly 2,000,000 per 

 sq. inch. The 'blueing' does not seem to have any serious 

 effect on the ultimate strength of the wood, but, of course, for 

 practical uses where stress and strain are set up, the elasticity 

 limit and modulus of elasticity are very vital factors. 



"The other lot, viz. the specimens from Inverness, all had an 

 exceedingly low limit of elasticity and an extraordinarily low 

 modulus of elasticity, and I am inclined to think that the bad 

 results obtained in these specimens were due to the fact of this 

 fungus attack." 



In considering the results obtained by Professor Hudson Beare, 

 it may be pointed out that the "blued" specimens used had 

 been infected naturally in the open, and that probably more 

 than one species of Cerafostomella was present, as well as other 

 sap -staining fungi such as species of Cladosporiuni and 

 Penicillium. 



Although in the case of the compression tests made by 

 Miinch, specimens of "blued" and healthy timber that were 

 truly comparable were obtained, it must be remembered that 

 the former had been produced by artificial infection with one 

 species of Ceratostomella only and that, before testing, all the 

 specimens were completely dried — a condition never found in 

 nature. No such exact comparisons can be made in the case 

 of the results obtained by Professor Hudson Beare, yet the 

 conclusions arrived at probably give a more accurate indication 

 of the effect of "blueing" on the strength of timber, for the 

 results upon which these are based were obtained from naturally 

 infected timber in the condition in which it comes into the 

 market. 



Hubert points out that a few cases have been noted where 

 " blue " wood steamed and bent for use in the manufacture of 

 furniture has failed under the bending process. In such a case 

 it is of importance to determine whether the failure is really due 

 to the Ceratostomella or to any wood-destroying fungi which may 

 accompany it. 



