1841.] 



THE CIVIL ENGINEER AND ARCHITECT'S JOURNAL. 



247 



am prepared to support Mr. Cubitt's opinion of the effect of tlie weirs. I do 

 not give any opinion of the proper mode of dealing nith the peculiarities of 

 the river Severn. 1 form my opinion on general scientific principles — that 

 the eficcts described, by Mr. Ciibitt will take place. I am now constructing 

 sea walls where there will be a weir, but I have never constructed one across 

 a river. The present weirs are of great length. I have heard of the mode in 

 which It is proposed to construct them. I see no use for a foot frame in the 

 present case. I think it will stand, as the stones are to be dropped in. I do 

 not think the water will have any eH'ect upon the stone so deposited. The 

 pressure is removed to a great extent by the sheet piling. The water will go 

 over' the top of the sheet piUng, and find its way through the stone works. It 

 will perforate in a gentle manner, and not disturb tlie stone work. In flood 

 there will be no fall at all because it will be the same height above as below. 

 I don't think I ever saw a large weir of this kind ; I have seen small ones in 

 canals, and I can apply theefiect produced in ether places to the present case, 

 Many weirs in this country and others are formed simply by loose rubble 

 stone. The finest I e\er saw, which is on tlie Boyne, is so constructed. A 

 weir of this description is made wafer-tight by the sheet piling above it. If 

 it should slip I should pack it again witli fresh stone ; It would be little ex- 

 pense. I am getting packing done now at 6il. per yard for labour. The 

 former stone would be available. I am aware of the object of putting the 

 weirs across the river; it is for the purpose of getting a higher level above. 

 It is placed obliquely, to afford greater facility for ilie passage of flood water. 

 I am of opinion that it would. I have myself proposed it. It is now being 

 done in the river Shannon. 1 am not engaged there, but I have made many 

 experiments on the subject. When the weir is placed right across the river 

 it diminishes the water way by the whole superficial area of the we'r. It is 

 the same whan it is placed obliquely, until the water flows over. As soon as 

 the water rises over the weir the circumstances are altered, and there wouU 

 be less obstruction, in proportion to the length of the weir, when it is placed 

 at light angles. The summer water would be at the same level, above and 

 below, in either case. In time of Hoods the water comes down at all points 

 of the weir at equal depth. It would always do so with an oblique, but not 

 with a right angled one. I don't see any reason why, in an oblique weir, 

 the water should make to the lower angle ; it would pass down parallel with 

 the axis of the river, or to the banks, if the banks are parallel. That is my 

 deliberate opinion. This principle may be applied in all cases of flood. The 

 water will not fall in the same mar.ner, but will take the shortest line. If 

 the water is rapid it \\ill form an acute angle at the crown of the weir. I 

 don't think water a foot deep will fall in this way. If you want to double 

 the capacity of the weir you should more than double its length. If you did 

 so with a weir directly across, you must widen the river. 



Mr. Cubitt explained, that w herever he proposed to put a weir, if the river 

 was not wider at that part than above and below, he proposed to w iden the 

 river at that part for the whole extent of the weir, to an extent at least equal 

 to the cross section of the weir; the consequence of which would be, if they 

 took the cross sections, the channel would amount to the sectional area, at 

 least, to the section of the river above and below. 



Mr. Mc'Ncil's examination, resumed. — I have made experiments as to 

 carrying a double quantity of water over a weir. I simply speak of the quan- 

 tity passing over, not of its approach. Not knowing the river, I can say no- 

 thing about the dredging. 



By Serjeant AVranghaui.— I do not know how much it is intended by the 

 Upton weir to pen up the water at the tail of the weir alxive. Whatever 

 height of water is penned back above the present summer level at half a mile 

 above Upton weir, will be so much abstracted from the water-way of the 

 river. When the current passes over the weir, it n ill pass at a higher level 

 th.in before the weir was there, by very nearly the depth of the water penned 

 back by it, added to the depth of the column of water passing over the weir. 

 In cases of flood the section of water-way for carrying off the flood will not 

 be diminished to the extent of the water penned back, because the dam below 

 is at the same time increasing in height, until it comes to the same level, 

 when the weir becomes no weir at all. Supposing the water to be penned 

 back within a few feet of the top of the bank, the river above being con- 

 tracted, all the water that can pass will pass over the weir. 



Re-examined by Mr. Serjeant Merewethcr. — The question just put to 

 me relates solely to the capacity to retain, and not to obstructions and the 

 facilities of avoiding them. The discharge of water over the w eir will be 

 in proportion to the length of the weir. I have heard of this principle 

 for seven or eight years. The construction of the Breakwater in the Ply- 

 mouth .Sounds is the same as it is proposed to construct these weirs. I con- 

 sider it to be the best mode of constructing weirs. — I have been professionally 

 employed on many rivers. The weir on the Boyne stands very well. If the 

 force of a river be five miles per hour, it would strike a weir directly across 

 at the same force, but if the weir is oblique, the force which strikes against 

 it is represented by a line drawn at right angles, and if the hypothenuse is 

 five, the force that would strike that side would be nearly three. If a weir 

 pens up five feet of water for a mile the water becomes stagnant, while it fills 

 up to the weir; but if a fresh should come it would not produce any impedi- 

 ment to its passing over an oblique weir. 



(To be conthmid.) 



laiSCEIiIiANEA. 



Daguerreotype Portraits. — A new discovery was communicated at the last 

 sittings of both the Royal Society of London and the Institute of France in 

 Paris, which is one of the most important improvements made in the Da- 

 guerreotype process, particidarly when applied to the art of taking portraits. 

 Mr, A. Claudet is the inventor of this discoverj', which consists in the com- 

 bination of chlorine, with the usual preparation. It is suflicient to expose 

 the plate for cue or two seconds to the vapours of that gas, to render it so 



sensitive to the etTect of light, that the tiiue of cx))0sure in the camera obscura 

 is shortened from 4 or 5 minutes to 10 or 15 seconds. This result must be 

 of the greatest importance in taking likenesses, as the great difficulty in 

 getting a person to sit immoveable for so long a period as was formerly re- 

 quired, always acted as a serious obstacle, Mr. A. Claudet is entitled to the 

 warmest acknowledgments for his invaluable discovery, and for having been 

 liberal enough to communicate it to the public. We understand that the 

 inventor is carrjiug on his process at the Adelaide Galleiy, and that Ids 

 Ukenesses are exquisitely executed. 



The Priricess Royal Steam Pleasure Boat. — On Wednesday June 9th, this 

 newlr-built pleasure boat, propelled by the Archimedes screw, made her first 

 pleasure trip from Brighton to Arundel and back. She was very recently 

 built on the Tyne (under the direction of Messrs. Bass, W. Catt, jun., and 

 Collins, the committee of the owners) fi-om which port she arrived on the 

 8th June, in the short space of 48i hours, the distance being upwards of -400 

 miles. She is of the following dimensions : length of keel 81 feet, breadth 

 of beam 17i feet, depth of hold 10 feet, of immersion 6i feet, tonnage 101 

 tons register. There are two engines each of 23 horse power, the screw is 

 5 feet diameter, G feet pitch, and 34 strokes of the engine making 170 evolu- 

 tions is the regulated speed. The velocity of the boat is about 8 knots an 

 hour (equal to about 9} miles.) 



Horsham. — The new church of St. Mark's (the first stone of which was 

 laid in April 1840), was consecrated on the 3rd instant. It is in the early 

 English style. The new school-room adjacent is also completed. Now the 

 work is finished it is due to the architect, Mr. Mosely, and the builder, Mr. 

 Darby, to say that both design and execution are highly creditable. Still, 

 the continuation of the parapets the whole length of the bnilding, and the 

 adoption of stone in lieu of slate for the roof would have been decided im- 

 provements. Doubtless the funds influenced these matters. The church 

 contains 900 sittings, and the cost, including gas fittings, boundary wall, and 

 a few other extras, is less than £3500. It must, how ever, be stated that the 

 ground was a gift, as was also the use of a stone quarry. 



Faculty of Engiiieer'mg in the University of Dublin. — The authorities of 

 Dublin University seem to be anxious to aid in the present movement for ex- 

 tending instruction in the practical sciences, and have given notice of their 

 intention to form a facidty of engineering in Trinity College. The faculties 

 now are London, Durham, Glasgow and DubUn, and the schools Woolwich, 

 Chatham, Sandhurst, Addiscombe, King's College, University College, Museum 

 of Economic Geology, Putney, Durham College, Edinburgh Academy, Glas- 

 gow College, Dubhii College, aud the Mining School of the Royal Dublin 

 Society. 



Societe des Architectes. — A Society of Architects is in progress of forma- 

 tion at Paris, on the model of the Institute here, which we hope it will 

 worthily emulate. 



Pouvrs of Locomotive Steam.— K steam coach running at a moderate rate, 

 which is about 21 miles per hour, would run over a distance of 500 miles per 

 day of 24 hours, and at that speed would reach British India from I^ondoii 

 in about 8i days— or Pekiii in China in 11 days— or from Gibraltar to the 

 Cape of Good Hope in 10 days — or from Quebec to Cape Horn in 17 days — 

 or once round the globe in 51 days— or 7 times round the globe in one year 

 — or a distai;ce equal from the earth to the moon in about 16 months, or from 

 the earth to the sun in 500 years. — Greenock paper. 



Pompeii. — A search among the mins of Pompeii, which took place lately, 

 led to the discovery of a marble statue, a silver vase, and a quantity of gold, 

 silver, and bronze medals, in a good state of preservation. 



Locomotire for Common Roads. — A gentleman residing at Southwell, Dr. 

 Calvert, has constructed a machine, « hich he purposes to call " The Altenmic," 

 because he rides or walks in turn according to the ascending or descending 

 inclination of the road he travels. By merely rising from his seat, and 

 throwing part of the weight of the body upon the hands placed on a guiding 

 bar, he n-alls with less fitigue than he could do without the machine, espe- 

 cially where the ascent is not very steep. On descending he sits down and 

 rides s.i his easewiih considerable speed. The propelling action (the most 

 powerful that can be exerted, and one of the most lasting is that of rowing. 

 Nottingham Journal. 



Paper from Asparagus. — We have plea.sure in hearing that one of the most 

 famous paper manufacturers, M. Dierecks, of Ghent, has collected all the 

 stalks of asparagus that come from the tables d'hoic and great houses of tlie 

 town, in order to convert them into paper. Every evening two or three loads 

 of these fibrous stalks are carried to the rolling mill, and tlience to the stamp- 

 ing machine, which triturates them in the course of a few hours. The kind 

 of paste which is thus produced does not require bleaching. It is put into a 

 tub, and taken to the paper-making machine, from which it issues converted 

 into excellent white paper, the expense of which is not half that of paper 

 made from rags. We have no doubt that when this secret is once known, it 

 will be eagerly appropriated by all large manufacturers. Asparagus mixed 

 with the pulp of beet-root produces a kind of paper, which is even super.or. 

 — La Fanal. 



A Steam Organ. — M. Lax, jun., has just invented a steam organ, which can 

 be heard through the extent of a whole province. This instrument, consisting 

 of vibrating plates of metal, is so reguluted that it is acted on by steam of 

 four or five atmospheres of pressure. These plates are merely very large steel 

 bars, which can only be made to vibrate by very high pressure steam. This 

 monster organ is fitted for popular solemnities and inaugurations of railroads. 

 It may be placed upon a wagon in front of the engine, which will supply it 

 with the same steam that moves the piston in the cylinders. The sound of 

 this stupendous Instrament would over[)Ower the noise of the issuing steam,, 

 the worKing of the wheels, and the roaring of thunder.— le Fanal. 



