DUST PREVENTION AXD ROAD PRESERVATION, 1916. 
Table 3. — Location of guard-rails. 
Left. 
Station i+82 
Station 14 + 71 
Station 20-00 
Station 40-40 
Station 56-90 
Station 58+24 
Station 63+00 
Station 
Station 77+63 
to Station 4 
to Stat 
to Station 
to Station 
to Station 
to Station 
to Station 
to Stat 
to Stat 
ion 16+60 
2-5 — 7S 
42+26 
57+94 
59+68 
64+00 
ion 72+60 
79- 63 
Right. 
Station 1+41 to Station 4+66 
Station 22+59 to Station 24+75 
Station 24+88 to Station 26+00 
Station 40+10 to Station 43+76 
Station 55+06 to Station 59+06 
Station 63+25 to Station 63+6-5 
Station 67+3S to Station 72+34 
Station 77-rS4 to Station 79+28 
Total, 4,519 linear feet. 
TESTS OF MATERL4LS. 
Table 4. — Physical properties of trap rock used in the surface construction. 
Specific gravity 3. 00 
Weight per cubic foot pounds . . 1ST 
Water absorbed per cubic foot do 43 
Per cent of wear 2.6 
French coefficient of wear 15. 5 
Hardness 18. 3 
Toughness 13 
Cementing value Fair. 
Table 5. — Mechanical analysis of gravel and sand used in the surface construction. 
Screened J 
■Sflf clean sa * d 
rSH 5584 
mSsNos.j 5a ^- 
5 and 6. 
Sand-clay 
gravel for 
experi- 
ments Nos. 
7 and S. 
Pea-gravel 
for gravel 
experi- 
ments Nos. 
5,6,7 
and S. 
Retained on 2 inch screen 
Passing 2-inch, retained on 1-J-inch screen 
Passing li-mch, retained on lMnch screen ..... 
Passing 1-J-inch, retained on 1-inch screen 
Passing 1-inch, retained on f-inch screen 
Passing f-inch, retained on £-inch screen 
Passing §-ineh, retained on J-ineh screen 
Passing J-inch, retained on 10-mesh sieve 
Passing 10-mesh sieve retained on 20-mesh sieve 
Passing 20-mesh sieve retained on 30-inch sieve 
Passing 30-mesh sieve retained on 40-mesh sieve 
Passing 40-mesh sieve retained on 50-mesh sieve 
Passing 50-mesh sieve retained on 80-mesh sieve 
Passing SO-mesh sieve retained on 100-mesh sieve 
Passing 100-mesh sieve retained on 200-mesh sieve 
Passing 200-mesh sieve 
Percent. [ Percent. Percent. ] Percent. 
Total. 
100.0 
100.0 
