481 
PARK AND CEMETERY. 
of crushed limestone and torpedo 
gravel, mixed and heated in a revolv- 
ing cylinder and, while hot, combined 
with liquid asphalt. When thorough- 
ly mixed it is spread over the drive- 
way, rolled and surfaced with a thin 
mopping of asphalt, over which is 
spread fine crushed granite. Only 
enough asphalt is used to cement the 
particles of stone together. The re- 
sult is a pavement having the appear- 
ance of macadam, yet one that so far 
has been proof against disintegration 
by the friction and suction of auto- 
mobile tires. 
Most of the repairing and repaving 
have been done by the South Park 
Commissioners at a considerably less 
cost than under contract. 
Extensive improvements in the 
plantation in Washington park were 
made, 40,863 trees and shrubs being 
set out, adding two and ' thirteen-hun- 
dredths acres to the areat of planta- 
tion in this park. This was a .step 
taken, in the interest of the future. 
Consul Rufus Fleming at Edin- 
burgh, makes a recent report on the 
experience with various forms of tar 
macadam road construction and main- 
tenance. 
The Edinburgh county road survey- 
or gives the results of his observations 
in England and his experience in 
Scotland with respect to the use of 
tar and pitch as binding materials for 
stones used in making and repairing 
roads. The four methods of applying 
tar considered are: (1) Tar spraying, 
(2) tar macadam, (3) pitch grouting, 
(4) tar matrix. 
The above methods and cost per 
superficial yard over ordinary macad- 
am, detailed by the county road sur- 
veyor, are here summarized: 
Tar Spraying. — It is essential that ali 
dust and caked mud be removed from the 
road before the liquid is applied. After 
tarring, a slight sprinkling of whinstone 
screenings is spread over the surface. Hand 
tar spraying is considered superior to ma- 
chines, although it costs slightly more and 
takes longer. In this process tar is not 
so much a binder as a waterproof protec- 
tion to the road surface. It is soon worn 
away, however, and when broken up the 
road is thrown into an uneven and dirty 
condition. It is now admitted that tar 
spraying lasts only for one season. The 
life of a road subjected to much fast mo- 
tor-car traffic is increased by 15 to 20 
per cent when tar sprayed. One of the 
main thoroughfares in 'Edinburgh County 
costs on an average $1,460 per mile per, an- 
num to maintain as at present. If tar 
sprayed its whole width the cost would 
be $1,800 per mile, after allowing for the 
increased life of the road, as above indi- 
cated. 
Tar spraying is most suitable for country 
roads where expenditure is llm.ited, and 
New trees were planted which will 
take the place of trees now reaching 
old age and destined in a few years 
to die out. The new shrubbery adds 
greatly to the beauty of the landscape 
in various portions of the park. Steps 
were authorized at the same time for 
work to preserve old trees of long 
lived varieties, which are good for 
many years, if properly cared for. 
Some of these veterans are showing 
the effects of lack of food, the soil 
of Washington park being deficient 
in nourishment. Composted soil will 
be deposited near such trees, where 
it can be reached easily by the roots 
and supply the needed nourishment. 
A similar work of preservation will be 
carried on in Jackson park and along 
the older boulevards. 
The total expenditures for park op- 
erations for the year amounted to 
$1,036,920. 
The repair shops and store rooms 
were remodeled and re-equipped. The 
area occupied by these buildings is 
although .tarring the entire surface wo.uld 
be preferable, a width of 10 to 12 feet in 
the center would accommodate motors and 
protect the metal bed, allowing at least 
double the length being sprayed, and leav- 
ing the sides with a better foothold for 
horses during frost. 
Tar Macadam. — This consists of thorough- 
ly mixing the stone with tar and pitch pre- 
vious to its being laid on the highway. 
All stones should be dry, which necessi- 
tates preparation of the materiai under a 
covered structure. Tarring may be done by 
hand or. machinery. It is usual to allow 
the material to lie in heaps one to three 
weeks to mature before applying. The 
coatings are applied in three iayers of 2% 
and 1% inches and % inch stone, roiied 
separately, and finished with a thin layer 
of fine dry screenings. Tar macadam roads 
are easily cleaned, and the cost' of main- 
tenance on an average of years is less than 
ordinary macadam. It is siippery during 
frost and unsafe on gradients steeper than 
1 to 20. Under very heavy traffic it loses 
its bituminous surface in two or three years, 
and the top layer becomes separated from 
that below. This system involves a com- 
paratively heavy initial expenditure, and 
its general adoption on county roads would 
appear to be impracticable. 
Pitch Grouting, — This consists of applica- 
tion to a scarified road, roiied smooth, of 
a S to 4 inch coat of whinstone metal, con- 
solidated in a dry state, after which boil- 
ing pitch and tar is poured into the joints, 
sprinkled with small whinstone or limestone 
gravel, and rolled until thoroughiy hard. 
The composition is made up as foliows; 
Pitch (best coal tar), 1,100 pounds; re- 
fined tar, heavy bodied, 800 pounds; creo- 
sote oil, 100 pounds; total, 2,000 pounds. 
The mixture is applied to the roads at 
boiling point with spray cans, whinstone 
chips are immediate applied, and rolling at 
once undertaken. This composition is of a 
quick-setting nature, but retains consider- 
able viscosity. The surface must be thor- 
oughly dry before it is applied. The sur- 
face is smooth, but not slippery. The traf- 
fic is carried on the metal and not on the 
tar, as is the case with dry macadam, tar 
painting, or tar matrix. This is regarded as 
the best system for tarring country roads. 
184 by 528 feet, just west of Cottage 
Grove avenue extending south from 
Fifty-eighth street. The plant con- 
sists of three lines of brick buildings, 
one story high and forty feet wide, 
with two thirty-foot driveways sepa- 
rating them. The roofs of the work 
shops and part of the store rooms 
are of the saw-tooth patern, giving 
excellent light from the north. Else- 
where the regular hip roof is used, 
covered with slate. The floor area of 
all the buildings totals 57,330 square 
feet, equalling one and three-tenths 
acres. They are used for the follow- 
ing purposes: For store rooms for 
all small supplies, and for lumber, 
coal, steamrollers, hose, plows, carts, 
stoves and other materials and im- 
plements; a machine shop, a black- 
smith shop, a carpenter shop, a paint 
shop with varnish room, plumber’s 
and pipe-fitter’s shops, electrician’s 
shop, cement working room, boat 
storage, iron room, ice cream factory, 
and garage. 
BRITAIN 
Tar Matrix. — There are three methods 
of applying tar matrix. It is usual to 
slightly scarify the existing road surface. 
The first is to spread a layer of small 
gravel, previously tarred, to a depth of 
1 inch to 1% inches, on which is laid ordi- 
nary road metal. This is rolled until the- 
matrix is forced to the surface. In the 
second the road metal is spread first and 
well rolled in the dry state before the ma- 
trix, composed of tarred materials up to 
1 inch in size and to the foregoing depth, 
is applied. This is rolled until the inter- 
stices are filled with the matrix and a 
smooth surface has been obtained. A thin, 
finishing coat of finer tarred materials is- 
usually applied, sprinkled with dry sand 
or chippings, and rolled until thoroughly 
hard. The third or Gladwell system is a 
combination of the first two, having a 
matrix both above and below the metal. 
Rocmac. — Roads made on the rocmao sys- 
tem are claimed to be dustless, water- 
proof, economical, durable, and nonslippery. 
The solution is a chemical composition, 
made under pressure, the foundation of 
which is silicate of soda and sugar. The 
solution is mixed with a high-class $4 -inch 
limestone and gravel free from impurities. 
This is laid about 1 inch to 1% inches- 
deep on the road surface, which has been 
slightly scarified. On this is spread the 
ordinary macadam metal, about 3 inches- 
thick, and thoroughly rolled until the ma- 
trix entirely fills the interstices and epmes- 
to the surface. Owing to the simple prep- 
aration of the matrix and small plant re- 
quired, the work can be undertaken by 
ordinary workmen, but experiments have 
proved it expensive compared with pitch 
grouting. 
In Scotland, as well as England, county 
road boards that have experimented with 
tar macadam in constructing new roads 
and maintenance of old have practically 
abandoned it, the cost being prohibitive. 
Tar spraying of 10 to 12 feet in the center 
is generally regarded as the limit of eco- 
nomical treatment of macadam roads in» 
outlying districts, and this has been re- 
stricted to main thoroughfares and of vil- 
lage roads. For suburban roads it is like- 
ly that the use of pitch grouting will in- 
crease. 
TAR MACADAM ROADS IN GREAT 
