124 



THE CIVIL ENGINEER AND ARCHITECTS JOURNAL. 



April 



At page 382 of the woik just quoie'l there is an exact draw ng and description 

 af the tactory ventilating fan. 



On the 6th of June, 1836, I took occasion again, in a jiaper read before the 

 Royal Society, upon the subject of the malaria which then prevailed in the 

 Custom House, to investigate the principles oi ventilation by the fan, and to 

 demonstrate, by a numerous train of experiments, the great preference due to 

 h, as to effect, economy, and comfort, over chimney-draught ventilation. 

 Yet at tliis very time, the latter most objectionable plan was in progress of 

 construction, upon a colossal scale, for the House of Commons. About the 

 s.ime period, however, the late ingenious Mr. Oldham, engineer of the Bank 

 of England, mounted a mechanical ventilator, and steam chest heater, for 

 supplying a copious current of warm air to the rooms of the engraving and 

 printing departments of that establishment. Instead of a fan, Mr. Oldham 

 employed a large pump to force the air through the alternate cells of his 

 steam chest. He had introduced a similar system into the Bank of Ireland 

 about ten years before, which is now in full action. 



About two years ago, Messrs. Easton and Amos were employed to ventilate 

 the letter carriers' and inland office departments of the General Post Office, 

 of which the atmosphere was rendered not only uncomfortable, but insa. 

 lubrious, by the numerous gas lights required there in the evenings, This 

 task has been executed to the entire satisfaction of their employers, by means 

 of fans driven by steam engine power. The said engineers made, about the 

 same time, a set of machinery similar to that erected at the Bank of England 

 for warming and ventilating the Bank of Vienna. They are justly entitled 

 to the credit of having been the .Irst to execute, in all its bearings, the system 

 of heating and ventilating buildings, having special respect to the health of 

 tlieir inmates, wliich I urged upon the public mind many years ago. 



As fans of sufficient size, driven by steam power with sufficient velocity to 

 warm in winter, and ventilate at all times, the most extensive buildings, may 

 be erected upon the principles above described, without causing any nuisance 

 from smoke, it is to be hoped that the Chapel cf Henry VII. will not be dese- 

 crated by having a factory Vesuvius reared in its cLissical precincts, and that 

 the noble pile of architecture of the new Houses of Parliament will not be 

 disfigured witli such a foul phenomenon. 



* The following engravings, which we borrow from the London Journal, 

 show the construction of the iron cases. 



iSgi 



■Fii2 



r A 



' : i 



Fig. 1 is a transverse vertical section of the steam chest, for heating the 

 air ; fig. 2 is a plan of the same ; and fig. 3 is a perspective view, showing the 

 outside casing, also the pipe a, for admitting the steam, and the stop-ccck b, 

 for allowing the condensed water to escape. 



ON IRON AS A MATERIAL FOR SHIP-BUILDING. 



At the last general monthly meeting of the Liverpool Polytechnic Society, 

 the president, Joho Grantham, Esq., C. £., read a paper On Iron as a material 

 for Ship-building. 



Mr. Grantham commenced by stating that it was not without some hesi- 

 tation he ventured to occupy the time of the meeting with an inquiry into 

 the advantages of using iron as a material for ship-building — an inquiry 

 which was of deep and growing interest, and of great importance to the port 

 of Liverpool. He had sought for practical information from others on the 

 subject, but, having scarcely received any of a practical nature, he deter- 

 mined to take an independent course, and trust to his own observations 

 rather than waste his efforts on a fruitless search. In this he had been 

 materially assisted by the knowledge be possessed of the qualities of iron; 

 and, as a proof of the sincerity of his views, he observed that he had come 



to the determination, in conjunction with other gentlemen, of engaging 

 seriously in the business of building iron vessels. 



It was a mistake to suppose that vessels had only been recently constructed 

 of iron. He was in a position to prove that the construction of iron vessels 

 was not an invention of recent date — that the value of iron in this respect 

 had long been known, and that it had been making a slow but a sure pro- 

 gress towards its present improved state. Iron vessels had been built for 

 the English canals so far back as forty years since, and some of thern, he had 

 reason to believe, were still in existence. The first iron vessel that put to 

 sea was built by the Horseley Iron Company, and was called the Aaron 

 Mauby, after the name of the projector. She was constructed in the year 

 1820, and had been at work ever since, without requiring any material re- 

 pairs. The next iron steain vessel with which he was acquainted was built 

 by the Horseley company under his father's superintendence. She was put 

 together in Liverpool, in the year 1S22, and proceeded to her destination, 

 Lough Derg, on the river Shannon. She had been constantly at work ever 

 since, and was at present in good condition. She was now the property o£ 

 the Shannon company, who had six iron steam vessels at work, all in excel- 

 lent condition. Several iron vessels had been built in England. The first 

 built in Liverpool was by Messrs. Fawcett & Co., at their boiler yard in Oil 

 Street. One of the vessels built by this company was called the Alhurka, 

 and went on Lander's unfortunate expedition to Africa. Several other iron 

 vessels had since been built, of which some of those sailing from Liverpool 

 (o Glasgow were most conspicuous. Iron steam vessels had been employed 

 in fighting our battles in the east, among which the Nemesis acted in the 

 Chinese war. The Ironside steamer had been built in Liverpool, and was 

 the first vessel of the kind, of any magnitude, that ever went to sea. 



Mr. Grantham then proceeded to describe the ordinary method of con- 

 structing iron vessels, which he illustrated by diagrams and models. Iron 

 vessels, he said, were constructed of plates fastened by angle iron ribs placed 

 in different directions. He then described the construction of the keel, the 

 bow, the floorings, the ribs, the platings, and the plan of double and single 

 rivetting. He said that experience alone could decide the question as to the 

 best disposition of the plates. He expressed himself in favour of the lap 

 joint, and said it was groundless to suppose that the rivets could easily be 

 driven out of their places, for, although the head might be removed, the 

 remainder of the rivet was almost immovable. After showing that there 

 existed great facility in applying stringers in iron vessels, he proceeded to 

 make some remarks on the peculiarities possessed by iron vessels, and to 

 institute a comparison between them and timber ones. In the eonstniction 

 of a vessel a builder should study strength, great stowage, safety, speed, 

 durability, lightness of repairs, cheapness, and draft of water. He said he 

 was in a condition to prove that iron vessels possessed all those qualifications 

 in an eminent degree, and that they were superior in those several respects 

 to timber vessels. In the first place they possessed great strength. It had 

 been asserted that iron might answer verj' well as a material for the con- 

 struction of small vessels and not very large ones. This, however, was not 

 the case. The country was deprived of some of its finest oaks in order that 

 timber vessels might be constructed, while there was no particular form into 

 which iron could not he moulded by the smiths of England. In the latter 

 case they had no sap to encounter, no knots, no cutting across the grain ; 

 and everj- inch of material was, moreover, of value. It was a well known 

 fact that timber, after having been in use for some time, became brittle and 

 could not be bent ; but good iron did not become brittle. The facihty for 

 obtaining iron beams in one piece removed many difficulties. 



The lecturer next instituted a comparison between the modes of fastening 

 iron and timber vessels, and instanced the case of a copper-fastened timber 

 ship, ami the dreadful creaking of timber vessels at sea. He then alluded to 

 the shock which had been some time since received by the Nemesis, and said 

 that if a similar shock had been received by a timber ship the flooring of the 

 latter might have been broken. The damage done to the Nemesis, however, 

 had only amounted to about 30/. He said he could relate many other in- 

 stances of the strength of iron vessels in comparison with timber ships, if 

 time permitted. He next alluded to the qualification of stowage. He said 

 the shell of a timber vessel was greater than that of an iron one, and that 

 while a timber vessel could carry 200 tous, an iron one of similar size could 

 carry 250. In the case of steamers, the comparison was much more in 

 favour of iron as a material for ship building. The qualification of safety 

 was in a great measure identical with strength. In addition to the extra- 

 ordinary strength of an iron vessel, it would be almost impossible for a fire 

 to take place in the hold if proper precautions were used, and the atmos- 

 pheric air excluded. After showing the superiority of iron vessels over tim- 



