CONTROL OF DECAY IN PULP AND PULP WOOD 45 
Borax is a white substance, 5.3 per cent soluble in water at 70° F. 
and 7.4 per cent at 86° F. It is nonpoisonous and therefore safe 
for workmen to handle. It slightly darkens the pulp but not to an 
objectionable degree. About 17 pounds of ground wood and 5 pounds 
of sulphite were treated with borax at the laboratory; 450 pounds 
of ground wood were treated at the mills. The borax treatments 
at the laboratory held the pulp in good condition (with slight mold- 
ing in a few cases) for six to eight months. Tests lasting for from 
13 to 24 months gave quite satisfactory results. (See PI. XIV, fig. 
1.) The mill tests, with 54 to 84 pounds of chemical per ton dripped 
on the pulp back of the press rolls, were not so favorable, the pulp 
having molded considerably within six months. 
Boric acid is 4.8 per cent soluble in water at 68° F. and is colorless 
in solution. It is nonpoisonous and safe to use, but more expensive 
than borax. It gives a slight pinkish-brown color to ground wood. 
About 10 pounds of ground wood and 4 pounds of sulphite were 
treated with boric acid at the laboratory; 160 pounds of ground wood 
were treated at the mill. After six months, the pulp was somewhat 
molded but in fairly good condition. After 12 to 13 months it was 
still in fair condition, with no active decay present. 
Cymene-napMhalene mixture. — Spruce turpentine (crude cymene) 
is a reddish-brown liquid by-product of the sulphite mill. Naph- 
thalene is the white substance used commonly as moth balls. It is 
33 3^ per cent soluble in cymene at 122° F. 
Pulp treated with naphthalene alone remained in good condition 
directly under the crystals, but became badly molded elsewhere. 
(PL XV, fig. 1.) With cymene alone, severe molding occurred. 
(PL XV, fig. 2.) About 150 pounds of ground-wood pulp were 
treated with mixtures of equal parts by weight of the two substances. 
Four pounds per ton of this mixture preserved the pulp perfectly 
for 10 months. The writers advise the use of 1^ pounds of naph- 
thalene dissolved in 6 pounds of cymene to a ton of dry pulp. To 
facilitate uniform application, the chemicals should be emulsified 
with the aid of rosin soap and diluted with water. (PL XV, figs. 3 
and 4.) 
Sodium fluoride is a white salt 4.3 per cent soluble in water at 
64° F. It is perfectly safe for workmen to handle and causes no 
chemical discoloration of the pulp. At the laboratory about 11 
pounds each of ground wood and sulphite were treated with sodium 
fluoride; at the mills 735 pounds of ground wood were so treated. 
The mill application of 18 to 28 pounds of chemical per ton gave 
somewhat variable results up to 16 months, the pulp in some cases 
being only slightly blue-black molded and in others rather badly so. 
It was, however, free from decay. Thirty-seven pounds per ton 
preserved the pulp very well, permitting only slight molding after 16 
months. Part of the pulp at the mill was somewhat molded after 
six months, but not seriously. 
Sodium dinitrophenolate is a yellow salt producing a yellow solution. 
It is approximately 2.4 per cent soluble in water at 59° F. Although 
in its concentrated form it is considered an industrial poison, it is 
thought that in the dilution hereinafter recommended it will not 
injure the health of workmen, provided reasonable care be exercised. 
In the lower concentrations it colors the pulp slightly yellow, and in 
the higher distinctly so. This color readily washes out, but the 
