106 



ON SILICA AND SOME OP ITS APPLICATIONS TO THE ARTS. 



[1854. 



adapted than wood to the operations of the puddling furnace, 

 on account of their superior density ; they develop a greater 

 quantity of heat, and also produce a more regular current of 

 gas ; besides which, the interstices between the pieces of wood 

 permit too much air to pass. In the new puddling process, 

 the quantity of air introduced into the furnace is, so to speak, 

 mathematically regulated ; the combustible mixture, and the 

 current of air which serves to ignite it, are admitted separately 

 into the laboratory. Here the fireplace must be of entirely 

 different dimensions. It is very long vertically; the grate is 

 veiy low, and composed only of a few bars to support the wood ; 

 the air no longer enters freely into the fire-place ; the bellows 

 send a graduated current of air under the wood, which traverses 

 it, producing its distillation. On account of the pile which 

 the air is obliged to traverse, this distillation takes place, so to 

 speak, in a gradual and progressive manner ; the air thus ad- 

 mitted into the lower part is in proportion to the quantity of 

 ligneux required to be carbonised in a given time. The cur- 

 rent of combustible gas which is found in the pile of wood 

 passes into the laboratory, where the puddling takes place, and 

 is met by a current of air carefully regulated and driven through 

 a pipe; thus the laboratory obtains, instead of an ordinary 

 flame, a combustible gas, free from all traces of pure oxygen. 

 Nothing is more easy, when one understands the composition 

 oi ligneux, than to know the exact quantity of air to admit 

 into the furnace ; but in what proportion shall the whole amount 

 of this quantity be divided ? How much shall go to the fur- 

 nace, and how much to the laboratory ? This is a cjuestion 

 which experience alone can answer. We can only say in gene- 

 ral that the latter proportion depends upon the more or less 

 combustibility of the mixture of gases, and consequently on 

 the temperature required in the furnace, the rapidity of the 

 distillation and the operation itself. 



This last term has evidently in all cases a limit, which fixes 

 the proportion to be established between these two currents of 

 air. Registers also connect them with each other, which can 

 be managed by the workmen themselves. This mode of coni- 

 bustion is very remarkable, both theoretically and practically; 

 it produces a very great regularity in the labour, and gives a 

 current of very pure gas; the purification of the oast iron is 

 thus eflfeoted under the most favourable circumstances, and 

 even very impure kinds give excellent iron. It is quite other- 

 wise, it is well known, with the ordinai-y method of puddling 

 with coal, and we may assert in general, that the impurity of 

 iron is attributable less to the cast iron than to the imperfection 

 of the mode of reviving. In the United States the cast iron 

 made with wood or anthracite would never be of a very bad 

 quality ;* the admirable perfection of the puddling with 

 ligneux would warrant the excellence of the products of the 

 new method. It now remains, and this is the main point, to 

 consider the economical conditions of the question. 



The following are the facts of the case, the exactitude of 

 which we will warrant. 



The consumption of cast iron, labour, and ligneux are per 

 on of iron : — 



Cast iron, 



f For the puddling, 

 Labour i For forging and rollin 



( Sundry processes, 



r • / For the puddling, 



-^ 1 For forging and r 



tons 1-242 



days 3 -§6 



:, " 4-69 



" 2-80 



tonsl-20X ^ ,„ 



oiling, " 1-30/*' °" 



) Ul-35 



This estimate may serve to establish the special expenses in 

 each particular case. In order to establish the general expen- 

 ses, it will be necessary to obtain information on the following 

 points : — 



1st. The purchase of land. 



2nd. The price of building materials, stones, bricks, clay, 

 &c., &c. 



It will be important, in order to diminish as much as possible 

 the total amount, to choose a situation where wood is cheap 

 and abundant, and in the neighbourhood of the mines, from 

 whence the ore could be brought at a small expense (In case 

 it should be preferable not to manufacture the cast iron, this 

 last observation applies to the cast iron which it would be 

 necessary to buy.) It is also important to take into account 

 the means of transport of the produce to the gi'eat industrial 

 markets, by canal or railroad; the price of labour, &c., &c. 



It would be well perhaps to annex to the establishment a 

 manufactory of cast steel ; the ligneux would be very suitable 

 for this species of manufactui'e, and it would be veiy easy to 

 prepare for this purpose iron of the best quality. The estab- 

 lishment of the works required by this new method must be on 

 a very large scale; its success depends almost entirely on the 

 employment of the most economical means of manufacturing 

 ligneux ; this condition can only be fulfilled by preparing the 

 ligneux in great quantities, and consequently the metallurgic 

 apparatus must be very numerous. 



The solution of this problem which we have been examining 

 is in the highest degree important to the future progress of 

 industry in the United States. It will enable them to employ 

 to advantage the mineral wealth scattered over their territory, 

 and upon a point of the utmost consequence will render them 

 independent of other nations. It therefore eminently deserves 

 the attention of the metallurgist and the manufacturer. 



On Silica and some of its Applications to t&e Arts.* 



BY EEV J. BARLOW, M.A., JF.R.S., V. P.H.I. 



* It remains to be seen, perhaps, if it would not be advantageous to 

 manufacture the cast iron also with ligneux. 



Silica is one of the most abundant substances known. 

 Quartz, common sand, &c., flint, chalcedony, opal, &c., and a 

 variety of sand described by Mr. J. T. Way,-}" may respec- 

 tively be taken as examples of crystallised and uncrystallised 

 silica. Under all these forms silica is capable of combining 

 with bases as an acid. Heat is however essentially necesssary 

 to effect this combination, a combination of which all the well- 

 known silicates, whether natural, as feldspar, mica, clay, &c., 

 or artificial, as glass, &c., are the results. The common forms 

 of insoluble glass are produced by the ttnion of silica with more 

 than one base. But, when combined with an alkaline base 

 only, silica forms a soluble glass, the degree of solubility of 

 which depends on the proportion which the siliceous acid bears 

 to this alkaline base. This soluble sOioated alkali (or water- 

 glass) may be prepared by various processes. If sand be used, 

 15 parts of find sand, thoroughly incorporated with 8 parts of 

 carbonate of soda, or with 10 of carbonate of potass and 1 of 

 charcoal, fused in a furnace, will produce a silieated alkali 

 which is soluble in boUing water. Messrs. Ransomes obtain 



* Substance of a Lecture delivered at the Royal Institution of Great 

 Britain, April 7, 1354. 



f Quarterly Journal of Chemical Society, July 1, 18.53, and Jotu-nal 

 of Royal Agricultui'al Society, Vol. xiv. p. 1. 



