6 
BULLETIN 1439, U. S. DEPARTMENT OF AGRICULTURE 
relating to them will be given. This season's results showed that 
linseed oil and fish oil were the most satisfactory of the three other 
adhesives, with linseed oil perhaps slightly the better of the two, but 
the difference was very slight. The price of linseed oil in barrel 
lots in April, 1923, was $1.17 per gallon; that of fish oil, 79 cents per 
gallon. As the difference in effectiveness between linseed oil and fish 
oil was so slight, and the difference in price was so great, it can be 
seen that fish oil was the best all-around adhesive used in the season 
of 1923. 
EXPERIMENTS CONDUCTED ON A LARGE SCALE IN 1924 
From 1921 to 1923, inclusive, all of the experiments with adhesives 
were conducted in a small way, small sprayers and very limited 
areas being used. In 
1924 these experiments 
were conducted on a 
larger scale, with high- 
power sprayers (fig. 1). 
The adhesives tested 
were linseed oil, fish oil, 
corn oil, lead oleate, 
flour, a proprietary 
casein product, soap, 
and a proprietary mis- 
cible oil. Two large 
areas in Somerville, N. 
J., were used; one, on 
Watchung Ridge, con- 
taining about 34 acres 
of deciduous growth, 
including more than 25 
different species, and 
the other in Dukes 
Park, containing 9 acres 
of solid blue spruce. 
EXPERIMENTS WITH DE- 
CIDUOUS TREES IN NEW 
JERSEY 
On Watchung Ridge 
10 different plots, 7 of 
4 acres each, and 3 of 2 
acres each, were under 
observation. Figure 2 
presents a diagram oi 
this area, with the num- 
bers of the several plots. 
On these, respectively, 
the following adhesives 
were tested on the plots 
referred to by the numbers: Plot 1, soap; plot 2, corn oil; 3, fish oil; 
4, linseed oil; 5, proprietary casein product; 6, lead oleate; 7, fl° ur 
8 and 9, proprietary miscible oil; 10, arsenate of lead, without added 
substance. 
Fig. 1.— High-power sprayer in operation at Watchung Ridge, 
Somerville, N J., 1924 
