For any subsequent period, assuming the cost of repaving to be $1.25 per square yard, the expense will be $0.1345 per yard, and for fifty-four years an average of $0.147.

0.1036.07.04+0.2136 for first period.

For any subsequent period, assuming cost of repaving to be $1.25 per yard, the annual expense will be $0.1485, or an average for forty-five years of $0.17 per year.

Table No. 55 shows the above results condensed.

In 1898 the city of Minneapolis, Minn., awarded a contract for asphalt pavements for $2.15 per yard with a ten years' guarantee, and an additional price of 10 cents per yard per year for the next ten years after the expiration of first guarantee. Assuming the interest charge to be 3 per cent, and the bonds to mature in twenty years, this pavement would cost 15 cents per yard for the first ten years, and 25 cents per yard for the additional period, but with no other charge, except for maintenance, for the remainder of life.

Table No. 56 shows the pavement mileage of eight of the principal cities of the country on January 1, 1900, except Washington, which is computed for July 1, 1899; also the mileage as it existed in 1890 except as noted. This table is given to show the change

in character, as well as the amount of pavement, during the last decade. This is particularly noticeable in the case of Philadelphia, where the increase has been 328 miles. Asphalt has increased 210.7 miles, stone block 232.6 miles, brick 99.7 miles, and macadam 105.5 miles, while cobble and rubble stone pavements have decreased 378.8 miles. The actual amount of new pavements laid in nine years was 666.9 miles, not including streets repaved with the same material. While a great portion of this work was done at the expense of the street-railway companies, it is a remarkable record. that will probably never be equalled by any other city in the world.

Total....

317.65 550.57 762.2 1050.2 341.75 435.21 133.31 216.64

In the eight cities mentioned, asphalt, stone-block, and brick pavements have increased from 1043 miles to 2195 miles, or 111 per cent; while stone block has increased from 776 to 1084 miles, or 39 per cent; asphalt has increased from 246 to 942 miles, or

283 per cent, and brick from 20 miles to 169 miles, or 745 per cent. The actual increase in each case is:

Stone
Asphalt
Brick

Miles.

307

696

149

Another important fact will be observed from this table: the increase in the amount of asphalt pavement.

In 1890 there were 246.26 miles of asphalt in these cities, except as noted in Boston and Philadelphia, and in 1900 this mileage had increased to 941.58 miles. These figures speak more forcibly than any other words can as to the popularity of this pavement. Wood, it will be noticed, has never been used to any extent in any of these cities, except in Chicago, where it has increased about 350 miles. Brick has had a great increase in Philadelphia, and has been introduced in several others.

Openings in Pavements.

One of the great sources of trouble to pavements is the frequent cuts made in it for repairs and connections to subsurface construction. Fifteen years ago it was thought that when water, sewer, and gas mains, with house connections to each lot, were laid in a street, it would be tolerably free from disturbance for some years. But in the days when telegraph, telephone, and electriclight wires are required to be placed underground, when pipes for heating and refrigerating purposes are being laid in our public streets, when changes in and repairs to street-railway construction are constantly going on, it seems as if, in many cases, a pavement is hardly free from the contractor before it is being torn up by the corporation or the plumber.

This matter is very difficult to regulate, especially when so many changes and improvements are being made in subsurface construction. It would seem, however, that the best way to prevent streets from being torn up is to provide for all underground construction before the pavement is laid, and then give no permits for openings within a stipulated time except in extreme cases. When a street is ordered improved, every householder on the line of improvement, and every corporation having any property at present or in pros

pective on the street, should be notified to make all needed repairs or extensions at once, under a penalty of a refusal to grant permits for extensions for a term of years. All repairs should be hedged with such conditions and requirements as to make it so expensive that corporations would find it to their interest to make all possible repairs in advance.

If a new building be constructed on a paved street, it must have connections to the different street mains. If these sewers have not

been previously laid, the pavement must be opened.

The city of Rochester has the power to construct sewers with their attendant connections, lay water-services, etc., under the same contract by which the pavement is laid, and assess the cost against the abutting property. Corporations having or projecting subways for any purpose are compelled to construct them in advance of the pavement.

It often happens, however, in most cities, that real-estate owners. are so anxious to increase the value of and sell their property that pavements are laid far in advance of any subsurface construction.

When the work of pipe-laying comes to be carried out, the pavement is badly damaged and in many cases practically destroyed.

In the report of the Commissioner of Public Works for New York City for 1896 it is stated that during the year one mile in four of the paved streets was torn up for construction purposes, and that 59,000 separate openings requiring repairs to pavements. were made during the year, or one opening for every 40 feet of paved streets. In Brooklyn, N. Y., during the year 1896 35,000 openings were made in the streets of the city, or one opening for about every 75 feet of paved streets.

In the report of the Street Department of Boston it is said, that for the year ending January 31, 1898, 14,017 separate openings were made in the streets, with a total length of openings of 213.4 miles.

These figures are startling, but would probably be duplicated in every large city in the country in proportion to its size. It is true that the repairs are made at the expense of the corporation or plumber rather than at the cost of the city at large, but it must be remembered that the money, in every instance, comes eventually from the people, and that with proper precaution a very large

portion of it could be saved. When methods of construction have been developed and fully standardized, and when the requirements of modern civilization in regard to public wants and necessities have been fully satisfied, it is to be hoped that this condition of affairs will be greatly improved. In the mean time every effort should be made to have the pavement disturbances as few as possible, and replaced in a good and substantial manner.

It is almost impossible, however, to repair any opening in a pavement so that it will be as good as before disturbance. The new work will generally be a little above or below the old surface, and in either case this means abnormal wear. Then, too, however well the pavement may be laid, any settlement in the earth of the excavation results in a corresponding settlement of the surface unless laid on a base of sufficient strength to span the opening and sustain the load by its transverse strength. It was the practice in Brooklyn, N. Y., for some time to require all cuts made in the improved pavements, whatever the original foundation, to be replaced on a Portland-cement concrete base eight inches thick. Settlements under this rule were very rare.

Stone pavements on a sand base must always be relaid over connections with an allowance for future settlement, else a depression will certainly develop over the trench, requiring relaying. In the event of the former method, the ridge in the pavements is objectionable until it reaches its permanent position, and, unless the paver be possessed of rare judgment, it will always require some readjustment. This will increase greatly the wear of the material and, consequently, decreases the life of the pavement.