XXIX.] 



^ 



and fa 

 circuit 



RIGA FIR. 



247 





There are, besides the hand-masts, many straight 

 and fair-grown trees that measure less than 24 inches in 

 circumference at the base, which are simply termed 

 spars, or poles. There are also a few pieces occasionally 

 met with that exceed the maximum size of the hand- 

 mast, which are generally dressed approximately to an 

 octagonal form, and then, as at Dantzic and elsewhere, 

 they are called inch masts. 



In ordinary specifications for building, it is stipulated 

 the Fir is to be from Dantzic or Riga, as if they were 

 equal in quality ; but my experiments on Riga Fir, 

 though not nearly so numerous as those on Dantzic, 

 prove the former to be slightly inferior to the latter. 

 Tables CXXII. to CXXVIII. and CXXIX. to CXXXII. 

 show that the strength of the Riga is to that of Dantzic 

 Fir as follows, viz. : 



Transversely as 150 : 219 or, it is weaker by about 31 per cent. 

 Tensilely ,,4051 : 3231 ,, ,, stronger 20 

 Vertically ,, 5247 : 6948 weaker 24 



TABLE CXXIX. FIR (RIGA). 



Transverse Experiments. 



REMARKS. No. i broke a little short ; 2 and 3 with fractures 9 inches in length ; in 

 4, 5, and 6, the fractures were longer and splintery. 



