PARK AND CEMETERY. 
31 
The semi-high power sprayer includes 
all machines of four to seven horsepower. 
Such machines may be used for mist 
work, but are generally spoken of as 
“solid stream sprayers.” The solid stream 
is produced by using a straight open bore 
nozzle with one-eighth or one-quarter inch 
tip under 200 pounds pressure. Such ma- 
chines will throw a forty to fifty foot 
stream and in high tree work will neces- 
sitate the use of forty-foot and sometimes 
sixty-foot ladders. 
This was the type of machines used by 
the late J. A. Pettigrew when I came to 
the Boston parks in 1906. It is interesting 
to note here that the first solid stream 
spray used in America was devised by 
Superintendent Pettigrew in 1895 while at 
Prospect Park, Brooklyn, N. Y. This is 
described by Dr. L. O. Howard in the 
Year Book of the Department of Agricul- 
ture for 1896. It was a home-made affair, 
consisting of a portable steam boiler and 
pump connected up to a watering cart. 
For a nozzle an ordinary fire nozzle was 
used with a small bore. The machine was 
invented to fight the Tussock moth and 
the elm leaf beetle. It did the work well 
and much quicker and better than any 
other method then in use. 
The high-power sprayer must have an 
engine of at least ten to fifteen horse- 
power. This is the latest and highest 
type of spray machine manufactured to- 
day. This will pump seventy-two gallons 
per minute at 300 pounds pressure and 
will throw a 100-foot stream with a one- 
quarter inch straight open bore nozzle. 
The essential differences between the high 
and semi-high power machines are the 
greater height of the stream and the finer 
character of the spray after it reaches the 
proper height. In the semi-high power 
machine the spray is a coarse, drenching 
spray. In the high-power machine the 
solution is driven with such force that the 
spray is broken into a fine mist after at- 
taining the proner height. With such a 
machine the highest tree in Massachu- 
setts can be properly sprayed without a 
ladder of any kind. 
In 1908 I kept records of the work of 
the different Boston park sprayers which 
at that time were all semi-high power ma- 
chines. These records included five items, 
which averaged as follows: 
Daily interest (5%) and depreciation 
of machinery (12%) $3.79 
Labor, six men (one foreman, one 
engineer, four laborers) 15.00 
Team 6.00 
Poison, three (600 gals.) loads, or 
216 pounds, at 10c 21.60 
Gasoline, three gals, at 13 J Ac 40 
$46.79 
These showed an average cost per day 
of $46.79 for one semi-high power sprayer. 
These are the figures on which the de- 
partment based its charge of $48 a day 
or $6 an hour for the use of one of these 
sprayers whenever it was detailed on pri- 
vate work. That season two of these ma- 
chines spent two days working over a 
section of Commonwealth avenue and 
sprayed the trees at an average cost of 
52 cents per tree. These were medium 
size trees and not more than one-half of 
them required the use of a ladder. 
At another place twenty very high Eng- 
lish elms were sprayed at a cost of $2 per 
tree. Sixty-foot ladders were necessary, 
and as the spray was for elm beetle, the 
work had to be very carefully done. The 
top of the tree was sprayed from the top 
of the ladder and the outer branches from 
a point lower down on the ladder. At all 
times the work was done slowly and thor- 
oughly, the stream being always directed 
against the underside of the leaves, in or- 
der to properly place the poison for the 
feeding larva;. Such costs as these are al- 
together too excessive and are due en- 
tirely to the limitations of this type of 
machine for this kind of work. 
In support of this statement I have rec- 
ords of the high-power machine spraying 
900 trees (25-90 feet) at a cost of 10 cents 
per tree, and again 17,000 trees (25-90 
feet) at a cost of 16 cents per tree. A 
conservative figure would be 20 cents per 
tree for the highest of trees, providing 
they are near enough together to cover 
the cost of moving the machine from place 
to place. A further compression might be 
made in the amount of material sprayed 
out per day by the two types of machines. 
The high power will average 3,600 gallons 
per day, while the semi-high power is av- 
eraging 1,800 gallons. In steady woodland 
work, where the high-power sprayer does 
not leave its position for filling, but is sup- 
plied by a filling machine, i. e., a separate 
line of hose and pump stationed at some 
near-by pond or other water supply, the 
high-power outfit has averaged 7,200 gal- 
lons per day. 
There is probably no one individual in 
the country who has taken more interest 
in the development of woodland spraying 
than Col. William D. Sohier, chairman of 
the Massachusetts Highway Commission. 
He has kept spraying records for years. 
He states that the cost of spraying, in- 
cluding labor and materials, without de- 
preciation of machinery, has averaged for 
low power or mist machines $38 per acre; 
for semi-high power (poorer type), $16 
per acre, and for semi-high power (better 
type), $10.08 per acre. In 1911, in his re- 
port for the Summer Residents Commit- 
tees on the Gypsy Moth Work on the 
North Shore, he reports on an outfit of 
six high-power horse sprayers with a cost 
of $6.51% per acre. In 1912 his outfit was 
increased to fourteen high-power horse 
sprayers, three filling machines and one 
high-power auto sprayer. This year the 
cost was $4.59 per acre. 
In explanation of this last figure it 
should be noted that the increased econ- 
omy has been secured more by a proper 
adjustment of the different types of ma- 
chines for the work to be done than by 
any great improvement in the machines 
themselves. The three filling machines 
greatly facilitated spraying the larger 
woodlands, but the most marked improve- 
ment was noticed in the adaptability of the 
auto sprayer to the large mileage of road- 
side reservation characteristic of this North 
Shore district. The auto sprayed both 
sides of the roadway at once and covered 
an immense amount of territory. 
In speaking of this high-power type of 
sprayer Col. Sohier says: “We found that 
our new spraying machines were doing 
much more efficient and economical work 
than the older ones. They actually threw 
over the top of the trees and made a finer 
spray and were more economical because, 
with their additional power, nearly double 
the territory could be covered in one day 
with the same labor cost.” 
So much for the new high-power type 
of sprayer. While this is the ideal which 
has developed in a secetion of the country 
requiring an immense amount of high 
woodland spraying because of the ever- 
present gypsy moth, yet for the farmer with 
an orchard and a small wood lot a smaller 
powered machine is all that is needed. The 
bulk of the spraying is mist work in the 
orchard. But the elms will have to be 
sprayed for the elm leaf bettle, and if the 
farm is in Massachusetts the owner must 
be prepared to protect his other shade 
trees or even to spray his whole wood lot. 
Under such conditions a proper equip- 
ment is half the battle, and a light, semi- 
high power machine of five to six horse- 
power will do the business. 
We have such a machine at the Arnold 
Arboretum. It is a strictly home product 
and was evolved on the place. Four years 
ago we began with one fifty-gallon spray 
barrel. We have had to go slow in devel- 
oping our equipment, but having a definite 
purpose in mind, each step has been taken 
in the right direction, and at last our pres- 
ent semi-high pow'er outfit has been real- 
ized. Before making the last move we 
secured expert advice and then went ahead 
and put the thing together ourselves in 
the wintertime, when the stormy weather 
forced the men inside. The spraying work 
would be done much quicker and more ef- 
ficiently if we had a high-power machine 
to co-operate with the one we now op- 
erate. But as it stands, our little sprayer 
has many points to recommend it and has 
given excellent service day in and day out. 
I will describe it briefly next month. 
(To be continued next month.) 
