1842.] 



THE CIVIL ENGINEER AND ARCHITECT'S JOURNAL. 



179 



VELOcrry of water through pipes. 



(From Report of Lecture by Dr. iteUon in the Midland Counties Herald.) 



The calculations for the head of water necessary to keep up a given 

 velocity for every 100 ft. run of pipe, have been so ably deduced, from 

 experiment, by Mr. Rofe, of the Birmingham Watenvorks, that the lecturer 

 could not forego the pleasure of pointing them out a little more in detail, 

 and of giving the tables by which the necessary calculations were effected. 

 The tables were two, and were both deduced from absolute experiment — 

 not from experimenti conducted by means of tin tubes of small diameter, fit 

 only for laboratory uses, as there was too much reason to fear many of the 

 tables previously published had been constructed, but from the absolute cast 

 iron tubings themselves, as laid down in Birmingham and its vicinity. The 

 tables were two : in the first, V represents the table of velocities in feet per 

 minute, and T the constant numbers for those velocities :— 



T 

 8-62 



V 



60 



70 



80 



90 



100 



110 



120 



130 



140 



150 



160 



170 



180 



11'40 



14-58 



17-95 



21-56 



25-35 



29-70 



34- 



38-90 



44- 



49-50 



55-66 



6213 



In the latter D represents the diameter of the pipes in inches, and t the 

 constant numbers for those diameters : — 



D ' 



3 



4 

 5 

 6 



7 



-028 

 -053 

 •078 

 -104 

 -134 



As an application of these tables, the following problem was proposed ; it 

 having been premised that the formula for their use was 



T 



= H 



D X t 



where H represents the height, or head of water. It is required, then, to 

 determine what head of water will be necessary to send water by an engine 

 through 1,500 ft. of six-inch pipes to an elevation of 80 ft. at a velocity of 

 180 ft. per minute. Now, by the table we see that the constant number for 

 180 ft. velocity is 62-13, and the constant number to be added to 6 inches 



is -078, 



and 62-13 



6-078 



= 10-22 inches. 



which is the head of water required to keep up the velocity of 180 ft. per 

 minute for every 100 ft. run; which being multiplied by 15 (the number of 

 hundred yards through which it has to pass), gives 153 in., or 12 ft. 9 in. 

 This, added to 80 ft,, will give 92 ft. 9 in. as the column of water which the 

 pump must lift. 



Table for Segmental Arches and Semi-elUput. 



The column headed c contains the ratios of the span of the arch to 

 the rise, taken as unity ; the corresponding numbers in R are the 

 respective radii. In column w are the degrees and minutes in the arc. 



The column ir — multiplied by W D R will give the cubic contents 



u 



of the arch. The last column shows the length of semi-ellipses, of 

 which the half-minor axes are unity, and the major axes the figures in 

 column c. This multiplied by the width into the thickness, into the 

 rise, will give the cubic contents of the arch in question. 



The best formula for the cubic contents of a tube or cylindrical ring 

 isLir(R--rJ where L=length; R=external radius; r=:internal 

 ditto; Tr=3-14159. Since the external radiusr=the internal-^-the 

 thickness of tube, we have L tt (R=-r=)=L tt ( (r+i)=— r-)=:L 

 (2 d r+d'') where rf=the thickness. Now, supposing that in an iron 

 pipe d should=half an inch, rf- will=Tfu of a foot. Neglecting this, 

 as may be safely done for short lengths, the formula becomes 

 L T (2 d r) 



MEASUREMENT OF BRIDGES. 



The formula given last month for the contents of a segmental arch 

 was misprinted : it should have been 



where W=width ; D=thickness of arch ; R=internal radius+4 D ; 

 7r=3- 14159; a=number of degrees in arc. The following table will 

 facilitate computation. 



ANOTHER COMPETITION AFFAIR. 



Sir— I am requested by Mr. East to lay before you the following state- 

 ment of the disgraceful manner in which he, as a competitor in designs for 

 the new church at Kidderminster, has been treated by the Committee, and 

 their actuary Mr. Boycot. On the 10th of December last an advertisement, 

 of which the following is a copy, appeared in the " Times" Newspaper :— 



It is proposed to build a church in the parish of Kidderminster to contain 

 1250 sittings, of which 850 are to be free. Architects wishing to furnisli 

 plans for the same are requested to apply for farther particulars to WilUam 

 Boycot, juu. Esq., solicitor, honorary secretary ; and all plans are required 

 to be sent to him on or before Wednesday, the 22nd day of December next. 



Kidderminster, Nov. 26, 1841. 



You will observe it was published for the first time 14 days after date, 

 thereby affording 12 days for the preparation of designs. As it happened 

 we had at that time more leisure than usual, and made appUcation to the 

 said Mr. Boycot (who, by the way, loses no opportunity of advertising his 

 calUng,) for" particulars of the advertisement, whereupon we received the 

 following reply ; — 



Sir— The undermentioned are the particulars relating to the new churcli 

 to be erected at Kidderminster. 



I am, Sir, your obedien servant, 



Kidderminster, Dec. 13, 1841. W. Boycot, jun., Sol., Hon. Sec. 



1. That the church will be built, subject to the rules and conditions of 

 the incorporated society. 



2. That the expense must not exceed £3000. 



3. That it be built of stone. 



4. That there be a tower. 



5. That the architecture be Gothic. 



6. That there be a commodious vestry. 



7. That there be no chancel. 



8. That the news be deal painted and grained oak colour. 



9. That the whole of the galleries be free, and sucli other portions of the 

 church as may be requured to make up the number to 850 free sittings. 



2 C 2 



