Year: 1877

DEAR SIR In my former paper took up the question of the source of supply, as to quantity. On this one point there seemed 10 be difference of opinion among the citizens. In this pa. per l propose to show one or two other points, viz, evaporation, and quantity to be supplied. This one point, evapo ration, in this case is hardly necessary to be considered, as the area of surface is so small and conditions are such that it needs no comment. The allowance to be made for evaporation must depend upon the physical condition of the local. ity in which the reservoir is constructed for the Tate of evaporation, depending upon the rarefactiOn of the atmosphere, it must necessarily rise or fall with the condition affecting that rarefaction. The average temperature, the expention, the average rate of motion in the air, the ci, cumstances likely to affect the hygrome- tric state of the atmosphere or to change 1t with vapor in suspension must vary in every individual Case, and any obserya- ton upon all these modifying causes must be taken into account in detcrmiI ing the amount of evaporation of any particular reservoir. The experience from the use of reservoirs on canals ap- pears to indicate that during the hot Summer months ii is necessary to allow for an evaporation ranging from one sixteenth to One-twelth of an inch per day throughout the entire year. Also, very much depends upon the depth of the water in Il reservoir to decide the amount of the evaporation It is prL- posed to construct the reservoir at depth of about sixteen feet, and to feed by springs, which are within few feet of said reservoir. Water must become heated to some extent; a current of air must have an unbroken sweep at it's sur face before any evaporation will take place to any extent. The surface or area being so small, derth being uniform (some sixteen feep, it would be impossi- ble for any amount of evaporation. IL is proposed to construct this reservoir to hold some two million gallons, which we call storage, as well as a distribu ting reservoir. The springs are con stantly yielding their quantity and flow ing into aforesaid reservoir We thus | store up for future use, and have sup ply on hand thai will last for period of about one year, allowing that we use to each inhabilant 20 gallons per day. The consumption of water in town varies greatly on account of the difference of habits and of occupation among its n habitants, and also what may be styled 1 the public taste with respect to the ap- plcation to the use of water. It is more than questionable whether, under nor mal circumstances, the real average con sumption ever exceeds six gallons per n- diyidnal per dsy--that is to say, for mere personal services; and this quantity may be increased to ten gallons per head to allow for washing and other household purposes But as in all towns it is ne. cessary to provide for municipal services and to supply water for trade purposes, # is usual to calculate upon introducing double the quantity thus indicated, or to assume that the consumption will take place at the rate of 20 gallons per head per day. As there are no steam boilers or sewers we think this last-na quan- tity is ample and abundant

 Yours,

 B H HrrIL