XXIX.] 
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. 
Number 
of the 
specimen. 
Deflections. 
Total 
weight 
required 
to break 
each 
piece. 
Specific 
gravity. 
Weight 
reduced 
to 
specific 
gravity 
600. 
Weight 
required 
to break 
1 square 
inch. 
With the 
apparatus 
weighing 
390 lbs. 
After the 
weight 
was 
removed. 
At 
the crisis 
of 
breaking. 
Inches. 
Inch. 
Inches. 
lbs. 
lbs. 
I 
1-25 
•IO 
3 '°° 
580 
524 
664 
I 45-00 
2 
I -OO 
•IO 
375 
707 
584 
726 
17675 
3 
1-50 
•10 
3'30 
498 
518 
577 
124-5° 
4 
1-50 
•05 
4 ' 5 ° 
615 
534 
691 
15375 
5 
135 
'IO 
3'85 
677 
570 
712 
169-25 
6 
I'D 
•10 
3 '35 
5 D 
5 i 6 
608 
13075 
Total . 
775 
•55 
2175 
3,600 
3246 
3978 
goo'oo 
Average 
1 '292 
•092 
3 '625 
600 
I 
£ 
663 
150-00 
Remarks. —No. 1 broke a little short ; 2 and 3 with fractures 9 inches in length ; in 
4, 3, and 6, the fractures were longer and splintery. 
