661 
PARK AND CEMETERY. 
by circularizing the road authorities 
in different parts of the country. The 
consul summarizes the statistics col- 
lected as follows: 
In regard to the preparation of the road 
for treatment with tar. 56 surveyors pointed 
out the necessity of thoroughly cleansing- 
the road from dust by sweeping it first with 
machine brooms and afterwards with hand 
brooms. Other replies, while more gen- 
eral. indicate that the road should be in 
good condition. 
As to the kind of tar used and the price 
134 authorities used crude or ordinary gas 
tar; 25 used distilled or refined tar; and 
6 used oil-gas tar. The prices varied from 
2 cents to 8 cents per gallon, the usual 
price between 4 and 5 cents. Twenty-nine 
authorities used specially prepared tarry 
materials, such as Tarvia, Tarmite, Clare’s 
Patent . Tar Compo, and Dustabato. 
In 33 cases the area treated per gallon 
of tar was between 3 and 5 square yards; 
in 99 cases it was between 5 and 7 yards; 
in 19 cases, between 7 and 9 yards; and 
in 5 cases more than 9 yards. When spe- 
cially prepared tarry materials, oil-gas tar, 
or ordinary tar mixed with oil was used, 
the average spread to the gallon was 
greater than when crude or distilled tar 
was employed. 
Asked as to what material was spread 
over after treatment, 77 authorities re- 
plied that they used sand: 37 used small 
(Vi inch) granite chippings and granite 
dust; 10 used large Cover H inch) granite 
chippings; 14 used limestone chippings or 
dust; 8 used slag chips or slag dust; 19 
used road grit removed from the road be- 
for treatment; and 15 used local materials, 
such as shingle, pea gravel, cinder dust, etc. 
In 5 cases no material was placed on the 
road after treatment. Several survej'ors 
expressed the opinion that granite chippings 
are the best material. 
As to the method of spreading the tar and 
the cost, in $4 cases hand spreading was 
used, while machine spreading was prac- 
ticed in 49 cases. 
The average cost for treating the road 
surface, including all expenses of prelimi- 
nary sweeping, tar, sand, or other material 
spread after treatment, and labor, varied 
between 1,4 cents and 6 cents per square 
yard. The usual cost was 2 to 2^^ cents 
when machine spread and 2 V 2 to 3 cents 
when hand spread. Where two coats had 
been given the cost of the second coat was 
much lower than the first. 
In 61 cases the treatment lasted a sea- 
son. 6 to 9 months; in .54 cases, 12 month®; 
in 5 case.s, over 13 months; and in 5 cases 
less than a season. In several cases when 
giving the road a second treatment it was 
necessary to treat only the center of the 
highway, the sides remaining in fairly 
good shape. In some districts the treat- 
ments lasted two years. 
A copy of the development and 
road improvement funds act of 1909 
is on file in the Bureau of Manufac- 
tures, at Washington, as are the fol- 
lowing publications of the Roads Im- 
provement Association: “Highway 
Maintenance and Repair,” “Official 
Test of the Dust-Laying Qualities of 
Calcium Chloride” (1909 and 1910), 
and “Dust-Problem Statistics.” These 
will be loaned to interested parties. 
Tar Macadam Roads in Scotland. 
Consul J. N. McCunn, at Glasgow, 
reports that the roads laid with tar 
macadam several years ago in this 
part of Scotland have fulfilled all ex- 
pectations as regards durability and 
cleanliness. It has been found that 
to convert an ordinary macadamized 
road into a tar-macadamized road it 
is not sufficient simply to cover the 
old macadamized surface with the 
tarred metal. The surface must first 
be “scarified.” When the whole of 
the original surface has been so “scar- 
ified,” the tarred metal is laid upon it 
and rolled in. If the surface is not 
scarified, but the tarred metal simply 
laid down upon the old surface of an 
uneven macadamized road, the fin- 
ished road soon begins to show un- 
evenness of surface, and finally it is 
apt to break up at various points where 
traffic is heavy. 
It has been found by experience 
that granolithic or cement foot pave- 
ments are more satisfactory than foot 
pavements made by the Walker sys- 
tem of tar macadam, although the tar- 
macadam pavement is more agreeable 
to walk upon. 
The Three Ways of Using Tarvia. 
In this country the office of public 
roads in the Department of Agricul- 
ture took the lead with certain im- 
portant experiments at Jackson, Tenn, 
The experiments were widely studied, 
imitated and developed, until now it 
is considered that limitations and 
difficulties are well understood among 
up-to-date engineers. In fact, the 
study of engineers is now directed 
toward the refining of the details of 
handling and application of the tar 
binders at minimum costs. 
An old road with its interstices 
packed tight and hard with dust 
would absorb some compounds very 
little, while a new road of a more 
open te.xture would drink up the bi- 
tumen greedily and even allow it to 
percolate down toward the founda- 
tion and away from the surface 
where it was needed. A standardiza- 
tion of the bitumen products became 
necessary and as chemical analysis of 
these materials is exceedingly difficult 
and elaborate, the manufacturers of 
Tarvia standardized them according 
to factory processes and gave them 
the permanent trade-mark names — 
“Tarvia A,” “Tarvia B” and “Tarvia 
X.” 
The division into three grades was 
according to consistency. Tarvia A 
is a refined tar of medium consist- 
ency, being very viscid when cold and 
liquifying readily at the application 
of heat. Tarvia B is a fluid, requiring 
no heat to prepare it for application, 
while Tarvia X goes to the other ex- 
treme, being solid when cold and very 
viscid and dense when hot. 
On old, well-worn and tightly 
packed roads, Tarvia B is used, the 
process simply requires the sweeping 
of the surface and the spraying of 
Tarvia B evenly over the road from 
a sprinkling cart. The Tarvia B 
sinks into the road and hardens, not 
however, becoming brittle, but re- 
taining its viscosity for a year or 
more. The attractive feature of this 
process is its low cost and simplicity. 
The second problem is that of the 
better grade of roads which require 
the maintenance of a smooth and 
handsome surface, as in parks, ceme- 
teries, boulevards and suburban 
streets. For this work Tarvia A is 
employed. The road is swept, the 
Tarvia A is applied hot — it percolates 
into the macadam and then the top 
coating of fine screenings is spread 
and rolled, thus restoring the even 
contour of the road and correcting all 
APPLYING TARVIA X TO MACADAM, BROOKLINE, MASS. 
(Concluded on page VIII) 
