Morning journal and courier., 1885-09-04
TOMLINsON,S BRIDGE.

The Effect of a Large PassageWay at the Bridge-An Alleged 1mPor- tant Benefit to the Navigation of the Quinnfpiac-A Gain of Deeper Waters and Higher Tides-A Great Sanitary Advantage.
 The following valuable information was imparted to me this morning by my friend. Professor William F. Trowbridge of Colum-
 bia college, New York, (formerly professor at Yale) which professorship was ten dsred him while he was vice presi- l dent of the Novelty iron works of New York, then the largest marine engine works on the continent.
 It is an acknowledged fact that Professor Trowbridge ranks second to none in the at West Point (where each year he stood at
 the head of his class) gave him high posi- tion in the United States engineer corps. After his graduation he served in that corps many years with honor. Professor Trow- bridge imparted to me the following: ESTIMATED EFFECT OF INCREASING THE WATERWAY AT ToMLINsoN BRIDGE. The increase of cross section at low water is not less than 2,000 square feet; suppose the mean velocity of the flood tide to be one
 mile an hour Git is probably two miles,) a reasonable estimate. One mile is 3 5,2S0 feet, | hence 5,2S0x2, ,OOO will be the number of cubit feet increased which flows through the opening at Tomlinson bridge since the dredging to eighteen feet mean low water was completed; 5,2S0x2, ,000-10, ,560, 900 cubit feet per hour of flood tide. Then 1O,- 56O, ,OOOx6-and we have the total increase of water which flows through the enlarged sluice-ways on every tide-63, ,360, 900 cubit A | faot fo ha of pounds this is equivalent to one million, nine
 hundred and eighty thousand q, ,99O, ,0OO) tons.
 This is the increase in the flow at the sluices of Tomlinson's bridge which passes up and down 730 times year as the effect of enlarging the water way.
 Professor Trowbridge has given me the fol lowing rule to find the quantity of water which flows through an opening or chan nel:
 Multiply the cross section of the opening or channel ill square feet by the velocity in feet.
 If the velocity is expressed in feet, per seconds, minutes or hour, the result will be the number of cubit feet which flow in the same time.
 For example: If 8 current of mile an hour has velocity of 5,2s0 feet an hour, etc., etc., as above.
 The above coming from so eminent source seems to me too valuable to be lost, and have taken the liberty to put it in print for the perusal of many of our citizens who are largely interested in both the Mill and Quinnipiac ri vers and who to-day are bene
 fitted by at least foot higher rise of tide since the passage way was enlarged, which
 has been noticed as far up as the North Ha- ven bridge, proving that with proper dredg- ing the Quinnipiac can be utilized for. long distance, and that New Haven and ad- joining towns can have several niles of good serviceable water front. And this is not all The increased volume of water allowed to store itself in the Quinnipiae basin on the flood tide will, during the last hours of the ebb tide, when the harbor flsls have run bare, SCOUT the channel, giving better draught of water and also carry off seaward the sewerage, which must in time, if allowed to accumulate Gas it is at the East street sewer), be unhealthful to our city and great disadvantage to the movement of the port c. H. T.