1846.] 



THE CIVIL ENGINEER AND ARCHITECT'S JOURNAL. 



J97 



. applicable in practice. Smoke consists of vapours produced by the partial 

 conibustioD or distillatiou of coal, carrying up small particles of the fuel in 

 inechauical suspensioD, and deposilinp, by the combustion of one of their 

 fonstitueuts, carbonaceous matter in a fine state of division. The mode of 

 preventing this smoke is to admit a sufficient quantity of air to efl'ect the 

 conibustiou of the carbonaceous matter, when the vapours are of a suffi- 

 ciently elevated temperature to unite entirely with the oxygen of the air. 

 If the temperature be not sufficiently elevated, the hydrogen of the vapours 

 alone is consumed, and the carbon is separated in the fine state of division 

 referred to. The gases produced by the complete combustion of fuel are 

 colourless and invisible, and therefore do not come under the definition of 

 ihe term smoke. 



" As the prevention of smoke implies the complete combustion of fuel, 

 the result, as an abstract statement, always is, that more heat is generated, 

 and a saving of fuel effected, when it is so consumed as to prevent the 

 emission of smoke ; but although this theoretical conclusion is undoubtedly 

 correct, the practical results are not always consonant with this statement. 



" lu consuming smoke in the usual way a quantity of cold air is intro- 

 dnced into the tire, and as this must be heated up to the temperature of the 

 surrounding fuel, the loss of the latter may be equal to, or even greater 

 than, the saving of the fuel from the combustion of the products of distilla- 

 tion. This often results in the careless use of furnaces constructed on the 

 principle of smoke prevention, and thus leads to the contradictory state- 

 ments given by those who have used such furnaces. But in all carefully 

 conducted experiments the saving of fuel has been considerable, and the 

 reason of this will be at once perceived, when it is considered that in addi- 

 tion to the combustion of the products of distillation there is a large amount 

 of fuel saved by the combustion of a gas called carbonic oxide, formed by 

 the proper product of combustion, carbonic acid, taking up in its passage 

 through the incandescent fuel, another portion of carbon, which escapes 

 useless as regards the production of heat, unless burned by the air intro- 

 duced at the bridge of the furnace, for the purpose of consuming the pro- 

 ducts of distillation. 



" From these considerations, and from experiments conducted under our 

 inspection, with a view to determine this point to our satisfaction, we ar- 

 rive at the conclusion, that although from careless management of fires 

 there is often no saving, and that indeed there is frequently a loss of heat 

 in the prevention nf smoke, still that with careful management the preven- 

 tion of smoke is in many cases attended with, and may in most cases be 

 made to produce, an economy of fuel. 



" It may be unnecessary to remind your lordship that the cause of th* 

 emission of smoke in manufactories may be classed under three different 

 heads, the relative importance of which involves very different considera- 

 tions in any attempt to legislate for its prevention. These are— 1. The 

 want of proper construction and adjustment between the fire-places and the 

 boilers, and the disproportionate size of the latter to the amount of work 

 which they are expected to perform;— 2. The deficiency of draught, and 

 improper construction of the flues leading to a chimney of inadequate 

 height or capacity ;— 3. The carelessness of stoking and management by 

 those entrusted with the charge of the fire-places and boilers." 



It cannot for a moment be questioned, that the coutinued emission of 

 smoke is an unnecessary consequence of the combustion of fuel, and that 

 as an abstract statement, it can be dispensed with. But your lordship 

 will perceive that there are grave difficulties connected with a general law 

 to the effect that it shall be unlawful for chimnies, after a certain date to 

 emit smoke. With regard to steam-engines, the processes fur the preven- 

 tion of smoke have been matured, and in very many instances successfully 

 employed. In this case, therefore, a law to that effect could be most easily 

 and promptly carried out. In other cases mentioned in Lord Lincoln's 

 letter, such as distilleries, dye-works, &;c., the legislature has already 

 granted powers in the Manchester Local Act; and as there are certain in- 

 stances in which processes for the prevention of smoke have with theiu 

 proved successful, it may be anticipated that the nuisance arising from 

 these sources may be much abated, if they be subjected to the general law 

 with that forbearance and caution whicli, under certain cases, is so advisa- 

 ble. There are certain processes in glass-works, iron-furnaces, and pot- 

 teries, in which it is neither possible nor desirable to apply a general law 

 for the prevention of smoke; although the nuisance may be partially miti- 

 gated, by causing the steam-engines employed in them to be so constructed 

 as not to emit siuoke. 



It is useless to expect, in the present state of our knowledge, that any 

 law can be practically applied to the fire places of common houses, which, 

 in a large town like London, contribute very materially to the pollution of 

 the atmosphere; but it may confidently be expected, that by a wise ad- 

 ministration of a legislative enactment, carefully framed, a great progres- 

 sive diminution of the smoke of large manufacturing towns will be effected, 

 and that the most happy results will thus flow from this improvement, in 

 the increased health and moral feeling of their population, the intimate 

 connection of which with facilities for cleanliness has been so often pointed 

 out. 



PLATE-GLASS MAKING IN ENGLAND IN 1846, CONTRASTED WITH WHAT IT WAS IN 1827. 

 (Compiled from authentic data by Henrv Hovvard, Blackwall, and 4, Railway-Place, Fenchurch-street. 1846. 



In 1840. 

 Coals are landed at works near Loudon at about 13s. per ton. 



An annealing kiln contains 400 feet. 

 A casting furnace produces 4,000 feet per week. 



Open pots are used, requiring less fuel, and containing about 20 cnt. 

 each. 



Pearlasbes are about £23 per ton. 



The casting-table is heated underneath by cylinders, at scarcely any ex- 

 pense. 



An engine of GO-horse power will grind and polish at least 3,000 feet 

 per week. 



A grinding bench at Works grinds about 500 feet per week. 



A grindiugbench may be constructed to grind COO feet per week. 



A polishing bench at — Works polishes about 500 feet per week. 



A polishing-beoch can be constructed to polish better and cheaper nearW 

 1,000 feet per week. •' 



A company near London is making 8,000 feet per week, or more than 

 400,000 feet per annum. 



And that is insufficient, but they can make no more, having no room to 

 extend. 



The price of rough plate (i and } of an inch thick) is Is. 6d. to 2s. per 

 foot; (cost lOd. to Is. per fo»t.) 



And one compaujr has an order for 43 000 feet ! 



Wages are high, hut they do not amount to so much per foot as in 1827. 



The largest plates are made with perfect facility, at less than Ss per 

 foot. 



And this amount may be still further reduced to about 23. 6d. per foot. 



None of the houses can keep stock, but can only supply their customers 

 from hand to mouth, and that very inadequately. 



Summary — Average. — In 1827 Plate Glass sold for about 12s. per foot, to the extent of about 5,000 feet per week. 

 " In I83G Plate Glass sold for from 85. to Os. per foot, to the extent of about 7,000 feet per week. 



In 1844 Plate Glass sold for from 63. to 7s. per foot, to the extent of about 23,000 feet per week. 

 In 1846 Plate Glass sells for Ss. to Os. per foot, to tiie extent of about 40,000 feet per week. 

 May 30. — Now nearly 45,000 fett per week— (Exclusive of foreign glass ) 

 Looking at the extraordinary increase that has taken place, notwithstanding the severity of excise restrictions, and seeing that the demand now nro- 

 grtsses more rapidly than ever, even at Ss. to 6s. per foot,— if the price were reduced to 43. or 3s. 6d. per foot (which, free as the trade now u from 

 excise interference, would aUbrd ample profit), what must then be the demand ? 



In 1827 



Coals in London were about 31s. 6d. per chaldron in the Pool, which, 

 with lighterage, wharfage, and cartage to the works, rendered them about 

 40s. per chaldron, or 30s. per ton. 



An annealing kiln contained 200 feet. 



A casting furnace produced, say 1,200 feet per week. 



Hooded or covered pots were used for melting the glass, containing 

 about 12 cwt. each. 



Pearlashes were at a high price, and heavy duty on alkali made there- 

 from. Pearlashes were in 1836, £43 per ton. 



The casliug-lable was heated on the top by charcoal, at an expense of 

 £500 per annum. 



An engine of 32horse power ground and polished (12 hours to the day) 

 from 800 to 1,000 feet per week. 



A grindiug-beuch ground 200 to 250 feet per week. 



A polishing-bench polished, 200 to 250 feet per week. 



A plate-glasswork in London manufactured about 60,000 feet per annum 



The price of rough and moulded plate varied from 5s. to 6s. per foot. 



Wages were comparatively low. 



Large plates were made with great difficulty, and thecost on the average 

 is estimated at about lOs. per foot. 



The manufactures kept a very large stock on hand. 



