The Providence (R. I.) Water-works.
By the construction of the Fruit Hill reservoir the system of water supply for Providence is practically completed. The reservoir was filled in December last, and now supplies the water for the high service districts, which have formerly been supplied by direct pumping by the engines at the Hope reservoir. Hereafter the engines at the Hope station will not be run continually, but only as often as it may be necessary to keep the high service reservoir at Fruit Hill approximately full, and opportunity will be given for making such changes in this pumping apparatus as will materially reduce the expenses of operation.
The elevations of the two highest points in the high service districts supplied from this reservoir are 202 and 201 feet above mean high tide, the former being upon Tin Top Hill, so called, and the other near the intersection of Smith street with the city line, the static head at which will be about seventy-three feet, while the entire area of both high service districts will have an average static head of from ninety-two to 193 feet, dependent upon the elevation of the ground. It has also been arranged that a main pipe can be laid from the 24inch main, connecting with the Fruit Hill reservoir, which will transmit to the business centre of the city for fire purposes a static head of about 262 feet, thus furnishing an independent supply of water in case of an extensive conflagration w ithin that district.
A large area in the neighborhood of Mount Pleasant, which is situated within the high service limits, is still supplied with water from the low service, and as the pressure in this locality is inadequate both for fire and domestic purposes, steps should be taken at an early day to connect the same with the high service. This can be done by laying a twelve-inch pipe from Smith street to Chalkstone avenue, in either River avenue or in the proposed extension of Mount Pleasant avenue, the latter, however, being preferable.
The city now has three reservoirs, the united storage capacity of which is 152,000,000 gallons, sufficient to furnish a supply for the present ordinary uses for twenty-five days, in the event of temporary stoppage of the pumping engines at Pettaconsett. While, however, ample provision is made for the storage of the water after it is pumped from the source of supply, yet in order to provide a sufficient reserve in the event of an accident or temporary disarrangement of the main pumping engines, it is stated that additional pumping apparatus at Pettaconsett will soon be required.
During the past year there has been a very marked increase in the number of water takers, and for the first time since the introduction of water the receipts therefrom at the close of the fiscal year have been in excess of the cost of interest and maintenance.
A GREAT SUSPENSION BRIDGE Projected.—M. Stoffel, the well-known French engineer, proposes a bridge of remarkable construction for the mouth of the Tagus, at Lisbon, Portugal. It would be nearly twice the length of the Brooklyn bridge, while its spans would be to those across the East river as nine to five, or almost twice as great. While the Brooklyn bridge is ninety metres above the sea, the Lisbon will be 120 : there will be four spans altogether, resting on iron piers with masonry foundations. The most formidable difficulty to be encountered in this vast undertaking is the building of the piers, the water of the Tagus being very deep, but modern engineering is expected to be fully equal to this.