1839.] 



THE CIVIL ENGINEER AND ARCHITECTS JOURNAL. 



4(i9 



inediale liars :iie moved In tlic opposite one. Tliis niovonient, aided Ijy tlie 

 channelled surl'iu'c of the bars, breaks up the elinkers the instant they are 

 fornied, or jirevents tlieir formation, and thus keeps the air wax perfectly 

 free. Considerable attention has, from time to time, been paid to the im- 

 provement of the fire-bar, now beeome of so mneh importanee to the manu- 

 facturinji; comnmnity, by men eminently qnallHed, and several patents have 

 been obtained for this purpose, all of wliieh have been very consiilerable im- 

 provements over the ordinary fire-bar. The object of the inventors not being 

 always the same, has produced a great variety of jilans, wliich have hati more 

 or less merit. Urunton, and also Steel, with a view to an equal distril>ution 

 of the fire, made the grate itself revolve ; others have simply moved the tire- 

 liars, with the intention of preventing the adhesion of clinkers, and the con- 

 sequent obstruction of the air-way. This is the object of Miller's patent, 

 which, being simple in its princi]de, of easy construction, not requiring extra- 

 ordinary strengtii, aiid consequently no increased weight of metal, the object 

 is attained with little increased expense over the ordinary llre-liar. The ad- 

 vantages it secures are very considerable ; for not only, liy the perfect free- 

 dom from all obstruction of the air-way, is the combustion of the fuel and 

 its heating power eonsiderably increased, but coal of an inferior quality can 

 be used \vitho\it the usual etfect of choking up the grate. By the vigorous 

 combustion which this grate ensures, it prevents large masses of coal from 

 passing away unconsnnied in the form of smoke, and consequently nuist effect 

 a considerable saving in fuel. The ingenious patentee is the chief engineer 

 of th(^ extensive works of Messrs. Thomson Brothers and Sons, Primrose, 

 near Clithero, where these bars have lieen for some time at work, and have 

 fully realised the expectations of the inventor. — Manchester Gtiartlinu. 



An improvement on Barker's mile, for which a patent has been taken 

 out by Mr. Stirrat, of Nethercraig, near Paisley, consists (licsidcs an inge- 

 nious water-joint and the application of something like tlie steam-engine 

 governor) in a beautiful contrivance for preventing the friction which arose 

 from the centrifugal action of the water on the revolving arms of the ma- 

 chine. To remedy this, the patentee has bad the arms of his machine made 

 with an eccentric curve, calculated according to the height of the fall, so that, 

 when the machine is in operation, the water rushes out, at its full speed, in 

 a straight line from the centre, to the extremity of the arm, where its power 

 is xvliolly exhausted by action on the sides o])|>osite the orifices by which it 

 runs off. The adrantages of this machine are said to be very great. In the 

 first place, while, by the common water-wheel, in some circumstances, only a 

 small portion of the water-power can be used, and under the most favourable 

 circumstances not more than tj.") per cent., it is calculated that by this new 

 machine not less than 05 per cent, of the motive jiower of the water is ren- 

 dered available. Secondly, the most trifling rivulet, provided it have a gooil 

 fall, can be taken advantage of by the new machine; and, thirdly, the ex- 

 pense of tlie improved Barker mill is not more than one-fifth of the expense 

 of a water-wheel, to work in the same stream. — Aberdeen Ueraht. 



PROCEEDINGS OF SCIENTIFIC SOCIETIES. 



INSTITUTION or CIVIL ENGINEERS. 



(Continued from ji^ye 31 l.j 



Hay 28. — James Walker, Esq., President, in the Chair. 



Diriny Bell. 



Colonel Pasley stated the result of some experiments which he had made 

 with a diving-bell in the Thames and in the Medway. The common rectan- 

 gular diving bell, suspended from a vessel in a very strong tide, was com- 

 pletely swept tinder the boat, and in some other cases it swung round half 

 and lialf, or was twisted considerably out of its proper position. He attached 

 boat-shaped ends, and on descending at the half ebb of a strong flood tule, 

 the bell was iierfectly steady. He should thbik a bell fitted in this manner 

 would be exceedingly advantageous forgoing alongside of wTccks. He should 

 recommend the ends to be moveable, and if the wreck were athwart the tide 

 he should have only one end )iut on, and bring the blurt' end against the 

 vessel. An experienced diver had informed "him, that in the current of the 

 Danube, running seven knots an hour, the bell vibrated tremendously. Since 

 this arrangement had occurred to bini, he discovered that a similar one had 

 been iirojioscd to the " then Navy Board," about 20 years «go, by Mr. M'. S. 

 Smith, who had been employed under Mr. Rennie, but it does not ajipear to 

 have been tried. Colonel Pasley promised the Institution a more detailed 

 account of his experience on this important subject. 



Coke and Peat. 



Mr. Parkes stated, that he would take this opportunity of the presence of 

 Mr. Williams to lay before the meeting some specimens of French Peat, 

 which had been alluded to on a inevious occasion.* One of the specimens 

 was that olitained by allowing the particles to come within the influence of 

 the natural forces to which the atoms are subject. The slnfch as dredged up 

 from the bottom of the streams, in a state of great comminution, was put into 



* Minutes, January 8, 1839, page Ul.j 



moulds, and, contracting as it dried, aciiuired considerable density. Tliis 

 was an instance of density due to gradual drying ; the density became doubled 

 by this process. Mr. Parkes |ireseiitcd a specimen of coke from compressed 

 peat ; this Mr. Williams wouhl explain, as he had taken up tlie subject where 

 every one else bad left oft', and had succeeded in producing density by ine- 

 clianical means, at a moderate cost, and, by carbonizing the mass, in getting 

 rid of the volatile particles, which are injurious as a fuel; he thus produced 

 an extremely valuable coke. 



Another specimen was of the incrustation on the interior of a gas retort ; 

 it was a coke of extreme density and of great value for some imriioses, but 

 for what was a secret. This deposition accumulates until the interior of the 

 retort is almost filled up, leaxing no available s|iace for the charge. The re- 

 torts are bought for the sake of this coke, whicli is a perfect carbon. A thin 

 coating of carbonaceous matter, wliich would otherwise be carried off in the 

 gas, is deposited each charge. 



Mr. Lowe was not aware of the uses to which this coke could be applied ; 

 lint it was of extreme ilisuse to the gas-makers; he believed, however, tliat it 

 was used to produce an intense heat. It is sometimes stated to be a carburet 

 of iron, but a portion from the centre of the mass shews, on being tested, 

 not the least trace of iron. It arises naturally in the process of gas-making, 

 and the rate of its deposition depends on the temperature ; as in those retorts 

 which have a tendency to become too hot the deposition goes on exceedingly 

 fast. There were many curious facts connected with its deposition ; that in 

 a horizontal part is stratified in concentric layers. The njiper )iortions will 

 be perfectly sectile and form admirable crayons, that at the lower part »ill 

 scratch glass ; it decreases in density from the bottom ; a portion of the sides 

 partakes of both qualities. He suspected, that a large quantity was sold as 

 black lead. 



Mr. Williams remarked, that there were two kinds of peat, the one having 

 a density due to impurities ; this is useless for all ))uriioses of metallurgy. 

 But for the purest carbon, the upper surface of the moss must be used, and 

 an artificial density must be communicated to it ; it is only in this manner 

 that a dense and pure coke can be olitained. The peat iiaving this artificial 

 density is carbonized, by which all the volatile m.attcr useless in cnmbustion 

 is driven oft', ground, and then being mixed with a bituminous matter the 

 operation of nature in the production of various species of coal may be closely 

 imitated. 



June 4. — The President in the Chair. 

 The following were balloted for and elected : Samuel Castle Gant, as a 

 Graduate; and Earl de Grey, as an Honorary Member. 



A paper was read : 



' CJii the Dimen.'iions and Performances of the .irchlmedean Steamer.* By 

 Gkouge Rennie, F.R.S., &c. ivc. We gave particulars of this vessel in the 

 last number of the Journal. 



June 11. — James Simpson, Esq. in the Chair. 



The following were balloted for and elected : Richard Griflith, as a Mem- 

 ber ; and Thomas Penson and Robert Aytoun, as Associates. 



' On JVarniinfj and I'entilatinr/ Public Buitdiuys ami Apartments, with an 

 account of ttie metttods which have been most successfully employed for en- 

 suring a healthy state of the .Itmosphere.' By Charles Hood, I''.R..\.S. 



The author first treats of the constitution of the atmosphere; the .artificial 

 changes produced in it, and the eft'ect of these changes on animal economy. 

 The researches of chemists show that in atmospheric air, uucontaminatcd by 

 respiration or other means, there exists from 21'1 to 20-5 per cent, of oxygen, 

 78 per cent, of nitrogen, yL per cent, of carbonic acid, and a small quantity 

 of aqueous vapour. Besides these there are many foreign matters insensible 

 to chemical tests, but quite sensible to our organs, whereof many being easily 

 decomposable by heat, are resolved into their constituent gases; to this fact 

 is to be referred the wbolcsonieness and pleasantness of some artificial sys- 

 tems of heating, or the contrary. The hydrometric condition of the atmo- 

 sphere is most remarkably affected by change of temperature, as the quantity 

 of vapour in air of 52 ' F. may be estimated at ttttt^^^ ^^ *^'^ weight of air, at 

 ■>'y" V. at ^tb, and at 8(i" F. at ^th ; when then the temperature of the air 

 within the room is considerably above tliat of the air without, this increased 

 cajiacity for moisture is productive of ert'ects prejudicial to the health. More- 

 over if iron surfaces of too high temperature be present, the vapour may be- 

 come decomposed, its oxygen combining with the iron, and the hydrogen 

 becoming dift'used through the atmosiibere. Consequences prejudicial to 

 health from these causes have been repeatedly experienced in rooms heated 

 by a hot air cockle; these eftccts are not pecidiar to the hot air cockle, but 

 will result in a greater or less degree whenever artificial warmth is produced 

 from iron surfaces, the temperature of which much exceeds 212' F. The 

 dryness of the air may in some measure lie remedied by moisture, distributed 

 artificially, but the eft'ects from the decomposition of the particles of matter 

 cannot he obviatctl by any artificial means. The system of Mr. Bernhardt is 

 peculiarly open to these objections, as tlie jiipes nearest the fire must become 

 intensely heated ; as also the stoves introduced by Dr. .\riiott ; since, inde- 

 pendent of the difficulty of keeping down the temperature of the metallic 

 surface, carbonic oxide is produced from the coke, and carburetted hydrogen 

 is also formed in the stove. The gas stoves are also open to the same objec- 

 tions ; moreover the quantities of water, of nitrogen, and of carbonic acid gas 

 evolved by the combustion of the gas are extremely deleterious. In the 

 latter case aqueous vapour will be in excess, and consequently the due quan- 



