270 



THE CIVIL ENGINEER AND ARCHITECT'S JOURNAL. 



r August, 



instances wliere tlie apparatus lias worked satisfactorily for a number of years, 

 and a|)|>arently without ri&k or danger to the liuildings. At lioth places the 

 parties expressed themselves satisfied witli the apparatus, and appeared to 

 have uo apprehension beyond the alarm and excitement caused by the late 

 accident at Messrs. Crafts and Stell's. 



It is true that reflecting persons, and indeed the whole community, have 

 been seriously ajipreliensive of danger since that accident took place ; and 

 Mr. Davies's report, and the opinion of Mr. Ryder, «ccm conclusive on that 

 point. In fact, it could not lie otlier^vise, as the practical conclusions dc- 

 ducililc from the experiments arc clear, namely, the singeing of feathers, ex- 

 plosion of gunpowder, charring of wood, ike, aic in themselves sulticient evi- 

 dence of the risk to which the property of individuals is exposed. It is also 

 apparent, that no system of heating is safe where the water, circulating 

 through pipes of small ijore, is raised to a high temperature, and subjected 

 to the changes of increased and sometimes suddenly diminished pressure. 

 On this question, therefore, I have no hesitation in giving it as my opinion, 

 that >lr. Perkins's principle of heating is imperfect, and that mure pnrticu- 

 larly from its liability to be overheated, either by improjicr treatment or a 

 sudden change of temperature, to which the apparatus is at all limes ex- 

 posed. 



Mr. Perkins, in describing Ids apparatus, replies to these objections by 

 stating that, in order to maintain for any length of time an equal temperature, 

 it is only necessary to proportion the furnace to the time the beat is required 

 to be continued, and the damper will regulate the combustion of the fuel, 

 and the heat of the ))ipes. Uy this Mr. Perkins means, that the attachment 

 of his heat regulator or governor, as given in his description of the ap]iaratHS, 

 will so rcgidate the admission of air to the furnace, by the expansion and 

 contraction of the flow-pipe acting upon a series of levers, as to 0]ien or close 

 tlie damper according to the temperature or intensity of heat contained in 

 the flow-pipe. N'ow 1 have closely examined this |)art of tlie apparatus, and 

 although exceedingly ingenious on the part of the projector, it is nevertheless 

 inefficient in its operation upon the furnace, and cannot therefore be depended 

 upon under all the changes to which the whole series is from time to time 

 subjecle<l. Mhcther this arises from excess of heat in the coils on the one 

 Land, or from a diminution of temperature on the other, is immaterial, as it 

 appears that the apparatus, as now constructed, is liable, either through 

 neglect or otherwise, to almost all the changes of temperature indicated by 

 the experiments of Mr. Davies and Mr. Ryder. 



Mr. Perkins, in his description of the apparatus, ijives (Mr. Babbage's ex- 

 periments) the range of temperature in the How-pipe and chimney as follows : 



Thermometer Thennometer 

 on Flow.pipe. in Chimnev. 



185° 116° ■ 



225 130 



244 132 



249 176 



249 182 



249 178 



249 180 



249 . 182 



246 184 



247 140 

 235 135 

 229 2U2 



Giving a mean temperature during a period of 



6 hours of 23S- 



102° 



Being an exceedingly low temperature, and such as imder the regulations 

 prescribed by Mr. liabbage, would be perfectly safe. But com])aring the 

 above with the experiments of Mr. Davies and Mr. Ryder, -ne have (be tem- 

 perature of the flow-pipe equal to that of melted lead, nearly -JOO' in excess 

 of that which Was considered safe by Mr. BaTjbagc. It is clear that in a series 

 of experiments such as those conducted by Mr. Davies and Mr. Ryder, the 

 temperature of the water in the coils and in tlie flow-pipe, as it issues from 

 the furnace, might be raised to ncarlyihe melting point of iron ; but in justice 

 to Mr. Perkins, I am hound to observe, tliat it is only an experimental case, 

 no doubt carefully and properly conducted, but certainly not indicative of 

 tbe general working state of the apparatus. 



In Mr. Perkins's system of beatingthcre is, Ibclievc, considerable economy, 

 and convenience in its application ; it is not, however, the best, nor yet the 

 most wholesome or safe mode of heating. It appears to me to be liable to 

 the following objections :— 



1st. The increase of tcmi)crature to whicli the coils and pipes are exposed, 

 and the consequent danger arising from the ignition of floctdent matter, which 

 by accident or neglect might surround tbe pipes. 



2nd. The impurity of the air, caused by its contact with metallic surfaces 

 highly be.ited. 



3rd. Deficient ventilation, where means are not provided for carrying off 

 the impurities, and admitting fresh air at proper intervals. 



The above appear to me to be some of the more prominent defects of rthis 

 system ; it is. hcwever, a simple and ingenious apparatus, and jirovided cer- 

 tain improvements were introduced, I have every reason to behove it iinight 

 be rendered an agreeable, if not a safe and efficacious mode of heating. 



In this country it is obvious'that large sums of juoneyhave been expended 



on the uss and application of this apparatus ; and as numerous buildings, 

 shops, houses, &c., are already fitted with all the necessary furnaces, coils, 

 &c., and as it is impossible to change the apparatus for a better all at once, 

 it appears very desirable to adopt such measures as will prevent the possibility 

 of accident, and afford greater security to property. Kor these objects I 

 would suggest the attachment of a mercurial tube to the flow-pipes issuing 

 from the furnace, with a metallic piston to rise and fall, an<l by its action on 

 a throttle-valve damper to check the draught in the furnace, and thns reduce 

 the heat whenever the flow-pipe indicates an excess above the maximum tem- 

 perature. 



Again, I would recommend the flow-pipes to be incased in a perforated 

 iron tube, to a distance sufficient to render a reduction of the temperature 

 certain, and to prevent the possibility of ignition, even Vfhen in contact with 

 inflammable matter. 



These precautions being adopted, and having encircled the furnace by brick 

 work, I should, under such circumstances, consider the apparatus less objec- 

 tionable, and freed, in a great measure, from the danger which now sur- 

 rounds it. 



^VM. Fairbairn. 



.Manchester, /ipri! 7!f>, 1841. 



ON VENTIIATION OF THE COURTS IN THE OLD BAILEY, 

 LONDON. 



On tlie 0th nit. a Court of .\ldermen was held for the purpose of receiving 

 a report from the Gaol Committee on the important subject of the vcntilatioa 

 of the courts of the Old Bailer. Dr. Reid was present during the proceed- 

 ings. 



Sir M. Wood brought up the Rejiort of the Committee to whom it bad 

 been referre<l to consider Dr. Reid's plan for improving the ventilations of 

 the courts of tbe Old liailcy. The committee were of opinion that the plan 

 ought to be adopted. The (OTimittee recommended this Court to direct a 

 communication to the Committee for Letting the City Lauds, requesting they 

 will present a report to tbe Court of Common Council, for authority for the 

 work to be proceeded with under their directions accordingly. Sir M. Wood, 

 in conclusion, moved that the Court agree with the Committee in their Re- 

 port. 



The following is the plan, as described officially by Dr. Reid : — 



" My Lord and Gentlemen, 



" The defective state of the ventilation at the courts in the Old Bailey, 

 which I have examined according to your instructions, arises principally from 

 the following causes ; — 



" 1. The inadequate supply of fresh air. 



" 2. The imperfect discharge of tbe vitiated air, a large proportion of which 

 is returned indefinitely upon the person, instead of being removed with cer- 

 tainty and decision. 



" The severity of the currents, arising from inadequate diffusion, and the 

 necessary opening of doors and windows from time to time, when complaints 

 are great from the deficiency in the Supply of air. 



" 4. The imperfect nature of various parts of the apparatus in use, which 

 presents difi'erent causes that render the air less whulcsome and agreeable 

 than it otherwise would be. 



" 5. The contamination of the small proportion of air supplied to a great 

 extent vith vitiated air, more particularly from the hall and other passages. 

 In the kitchen there is a cesspool liaving no connexion with any drain, into 

 which about 30 pails of water are introduced daily during the sitting of the 

 Courts, all of which appears, so far as I have been able to ascertain, to mingle 

 by evaporation with the atmosphere of the kitchen, and to find its way to the 

 jiassages. 



" It will be olivlous that defects such as these cannot be eft'ectually remedied 

 without intioduciiig arrangements of proportionate magnitude, as in the 

 original construction of the courts, it could not be expected, from the period 

 at which they were built, that provision would be made for meeting the views 

 now entertained as to the nature and importance of ventilation ; while the 

 chambers below and above both courts, excepting on tlie roofs of the New 

 Court, are so niiicli occupied that few facilities are inesented for diffusive 

 ventilation, by which alone any degree of comfort can be given in places so 

 liable to a fluctuating attendance iis these courts must be. Under the cir- 

 cumstances, and proceeding upon the assumption that 2000 persons are as 

 many as it would be necessary to pro\ide nir for, according to the repUes to 

 the various inquiries upon which I entered in reference to this point, I have 

 to propose the following arrangement*. It may lie proper for me to premise, 

 however, that 2000 persons 12 hours a day in court require air for 28,800,000 

 respirations during that period, independent of what may be necessary for the 

 surface of the body : — 



" 1. Let a chamber lie provided for the reception of fresh air where it 

 shall escape much of the contamination which it receives at present from 

 ■eating-houses, chimnics, &c., in the immediate vicinity. 



".2. J,et the air be filtered from soot as it enters the chamber, washed, 

 when necessary with lime-water to remove various impurities, and finally he 

 propelled to the courts by a fanner worked by a steam engine. This arrange- 

 ment ajipears to be the only cconoiujcal plan that will insure the ventilation 

 of the courts, considering the pecuUarity of their position, and the manner ifi 

 whicli thoy.arebcmmcd in on all sides by different apartments. 



