38 BULLETIN 1451, U. S. DEPARTMENT OF AGRICULTURE 
fuel oil was the least effective of all, probably because of its failure 
to penetrate the soil readily. 
Considering all the oils studied, it was found that in general the 
lighter, more penetrating oils were more effective than the heavier 
ones. For this reason gasoline might have been expected to be the 
most effective of the four petroleum oils studied. Why it was not 
is not known. 
MONOCHLOROBENZENE 
Monochlorobenzene (C 6 H 5 C1) also is a light liquid and is obtain- 
able in quantity for about 12 cents a pound. Eight cubic centi- 
meters sufficed to kill barberries in 8-inch pots in 22 days. No field 
tests were made. 
NITROBENZENE 
Nitrobenzene (C 6 H 5 N0 2 ), a light liquid, was quoted at 11.5 cents 
a pound in 1,000-pound lots. When applied to the soil of 8-inch pots 
in which barberries were growing, 5.2 cubic centimeters caused their 
death in 20 days. This was a slightly better showing than was made 
by any of the other benzol compounds, with the exception of phenol 
and orthotoluidine. No field tests were made. 
PARANITROCHLOROBENZENE 
Paranitrochlorobenzene (C 6 H 4 N0 2 C1) is a liquid at ordinary tem- 
perature. When 5.2 cubic centimeters of it were applied to the soil 
around barberries growing in 8-inch pots death of the plants resulted 
in about six weeks. As the action was so slow and the chemical 
somewhat expensive, no field tests were made. 
ORTHONITROTOLUENE 
Orthonitrotoluene (C 6 H 4 CH 3 N0 2 ) is an oily liquid. Five cubic 
centimeters applied to the soil in 8-inch pots in which barberries were 
growing caused the death of the plants in about seven weeks. As 
larger doses would be too expensive no further tests were made with 
this chemical. 
PARATOLUENEMONOSULPHONIC ACID 
Paratoluenemonosulphonic acid (CJ3 4 CH 3 HS0 3 .4H 2 0) is a crys- 
talline substance. It was quoted at 30 cents a pound in 1,000-pound 
lots. A treatment of 5.2 grams applied to barberries in 8-inch pots 
failed to kill the plants. Some of the lower leaves died, however. 
No field tests were made. 
PARATOLUENESODITJMSULPHONATE 
Paratoluenesodiumsulphonate (C 6 H 4 CH 3 S0 3 Na) is a crystalline 
substance quoted at about 10 cents a pound in 1,000-pound lots. 
When applied to barberries in 8-inch pots 10 grams failed to kill 
the plants, though there was slight injury. No field tests were made. 
