XXVIII.] RIGA FIR. 331 



The straightest and best spars have simply the bark 

 taken off them, and the knots dressed smoothly, with 

 perhaps a few feet in length at the butt-end hewn, to 

 remove the swelling which often occurs at the base of 

 the tree. Beyond this, owing to their generally fair and 

 even growth, very little is required, and, as the alburnum 

 or sap upon this description of timber is not usually 

 more than about i inch in thickness, the waste sustained 

 in their conversion into masts is altogether insignificant. 

 These Riga spars (their generally small and medium 

 sizes being considered) are about the best to be met 

 with, and are in great favour with the mast-makers of 

 the royal dockyards, though somewhat less so in the 

 private trade. 



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. 

 The tables on the following and preceding pages 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 ,, 



