1849.1 



THE CIVIL ENGINEER AND ARCHITECT'S JOURNAL, 



115 



trougli-iron made. The interior of the pile may be filled, in any- 

 convenient manner. 



Tlie patentee does not claim for forming the piles from which 

 railway-bars are rolled, as it has been in practice; but lie claims 

 for forming the piles for making tyre-bars, square bars, round 

 bars, and flat bars; tee-iron, angle-iron, and trough-iron, with bent 

 bars, as described. 



MANUFACTURE OF WHITE LEAD. 



Thomas Richardson, of Newcastle-on-Tyne, chemist, for "im- 

 pi'ovements in the condensation of metallic fumes, and in the manufac- 

 ture of white lead." — Granted August 21, 1848; Enrolled February 

 21, 1849. 



The improvements relate, first, to the manufacture of white 

 lead, in the following manner. Tea lead is to be submitted in a 

 melted state to a slow current of heated air, in an ordinary red- 

 lead furnace, or in the iron pan employed for calcining hard lead, 

 by which means the tin contained therein will be caused to sepa- 

 rate from it and float upon the surface, together with a variable 

 quantity of the oxide of lead, which is to be removed with an iron 

 rake The completion of this part of the process is known by the 

 lead becoming so soft that it may be scratched with the fingei', 

 M'hen the remaining materials are to be taken away also. The 

 lead is then to be reduced into crystals by the desilverizing process 

 of Mr. Pattinson, or employed in a granular state. The prepared 

 lead is to be moistened by the application of certain proportions 

 of nitric or acetic acid of commerce, or nitrate or acetate of lead, 

 diluted with water until of equivalent strength, and the moistened 

 mass turned over from time to time, and, when sufficiently treated 

 in this manner, about 20 or 30 cwt. of the same is to be placed in 

 chambers, lined with lead, slate, or stone, the latter being preferred, 

 fitted into a suitable frame, provided with doors, and having spaces 

 between each of such chambers, into which spaces heated air is to 

 be admitted (by means of a pipe furnished with a stop-cock), in 

 order to keep the chambers at a proper temperature. Carbonic 

 acid gas, is to be introduced into the chambers with the prepared 

 lead, by means of pipes with stop-cocks ; the heat is to be kept up, 

 and steam admitted occasionally. At the expiration of from 10 to 

 14 days, the materials will l)e properly treated, wlien they are to 

 be removed from the apparatus, ground between a pair of stones, 

 and washed in a dolly-tub, which separates the metallic lead from 

 the white lead, the former being returned with a fresh supply to 

 the chamber. 



Secondly, the improvement relates to the condensation of me- 

 tallic fumes, which consist in introducing steam into the main pipe 

 connecting the furnaces, by means of a small iron pipe situate at 

 a distance of 2 feet or 3 feet beyond the furnace, and in building 

 near the chimney a tower, not less than 20 feet high, divided in- 

 ternally by a partition wall, which reaches nearly to the top 

 thereof; iron bars are placed across, upon which a layer of coke 

 or pieces of broken brick is placed. The fumes ascend up the one 

 compartment, but are intercepted in their passage down the other 

 by the layer of coke or broken brick, upon which water flows in 

 from the top. If the draught be not sufficient to draw through 

 the coke, it is to be increased by means of steam jets. 



VENEER CUTTING MACHINE. 



Pierre Armanh Le Comte de Fontainbmobeau, of 4, Soutli- 

 street, Finsbury, Middlesex, for ^''certain improvements in the ma- 

 chinery for cutting wood, and in laying and uniting veneers." (A 

 communication.) — Granted May 25, 1847. 



The improvements relate, firstly, to macliinery for cutting wood 

 into thin and continuous sheets of any desired width ; secondly, to 

 apparatus for pasting and doubling those said sheets, and their 

 application to useful purposes, such as for hangings of apartments, 

 &c. For the better comprehension of the invention, before enter- 

 ing into a detailed description of the manner of carrying it into 

 effect, it will be well to premise by an expose of the present state 

 of the manufacture. 



The mode of cutting wood in a cylindrical manner by means of 

 a knife tangent to the circumference has been already devised, but 

 up to the present time the mechanical means employed have proved 

 insufficient to produce practical results, and manufacturers have 

 not been able to operate but on small widths. It has never suc- 



ceeded completely ; and it may be added, that here endeavours 

 have entirely failed, notwithstanding the numerous experiments 

 which were essayed upon it — not because the system of cutting 

 wood in that manner was unattainable, but because neither the 

 mode of operating, nor the proper and rational mechanical disposi- 

 tions which such an operation required, were found out. But it 

 must be admitted that this operation is very delicate, and presents 

 very great mechanical difficulties. It is therefore only after many 

 experiments, attended with considerable trouble and perseverance, 

 that satisfactory results have been obtained by the invention here- 

 after described. 



From \vliat proceeds, it will be easily understood that the first 

 part of the invention is not the mere endeavour or idea of cutting 

 wood tangentially to the cylinder in a spiral form, but consists 

 really in the mechanical means or dispositions liereinafter described 

 for ol)taining such desirable results. 



The machine whicli forms the subject of this patent, by cutting 

 wood of large widths in a continuous manner, fulfils all the re- 

 quired conditions — namely, producing it with a great economy of 

 time and manual labour. Thus a piece of wood — a log of maho- 

 gany for instance, whatever be its size, set in tliis apparatus, is cut 

 in a continuous manner, without any interruption and with a velo- 

 city truly surprising ; which is the more remarkable as it is ob- 

 tained without sawing, but merely by cutting the substance on all 

 its surface simultaneously and cylindricaUy, so as to form a spiral 

 developed from the circumference to the centre. 



We shall in the present number confine our extracts from the 

 patent to the first part — viz. to machinery for cutting wood into 

 veneers. Tlie patentee proceeds as follows : — 



My means, which as it will be easily seen are entirely new, com- 

 prise : — 



Firstly, — The application of a sharp-edged and very thin blade, 

 held fast between two knives or straight rulers ending in basil, 

 which, while they keep tight the blade over all its length and near 

 its cutting edge, prevent it on one side from going too deep into 

 the wood, and on the other side force it to penetrate far enough 

 into it, and to the required degree, according to the thickness de- 

 signed for the sheets. That application, or rather addition of a 

 thin blade working between two knives, is of the greatest import- 

 ance for the success of the operation, and forms — I venture to say, 

 a mechanical principle quite new, not only in the apparatus herein- 

 after described, but also in all other machines for wood-cutting, 

 either from prisms, blocks, or logs. 



Secondly, — The disposition of a strong leader set immediately 

 above the knives, and resting constantly on the wood as fast as it 

 is cut. That pressing leader, which is of a quite new application, 

 is also of great importance in the operation, as it serves to keep 

 the wood fast over all its length, and close to the part which is to 

 be cut by the blade; so tliat, notwithstanding the knots, brambles, 

 and defects which the knife meets with, it is always perfectly sup- 

 ported, and cannot be the cause of any defect or accident. If 

 even the wood by its nature were very defective, uneven, and pre- 

 sented very little homogenousness in its different parts, it would 

 nevertlieless be well cut, and with all tlie precision and nicety that 

 could be wished for. 



Thirdly, — -The mechanism adapted for working the blade, and 

 at the same time the pressing leader in a continuous manner, is 

 proportioned to the velocity given to the piece of wood to be cut; 

 and it produces sheets of a surface constantly even, and of an 

 equal thickness upon all their width, from the beginning to the end 

 ot the spiral. The quicker the block turns the more the progres- 

 sion of the blade and leader is rapid, and so reciprocally, whatever 

 be the thickness previously regulated. 



Fourthly, — The addition to the machine of a moveable drum, or 

 cross-bar, provided with several arms, permitting to receive simul- 

 taneously a certain number of pieces of wood, and to cut them 

 into thin and rectangular sheets, instead of continuous sheets, 

 which in many cases enables me to make valuable applications of 

 my invention to bramble woods and others. 



Witliout the particular means which I have hereinbefore men- 

 tioned, and which constitute the whole of my invention, that is to 

 say, all the principal or working parts of the macliine, it is quite 

 impossible to obtain the practical results which I produce, espe- 

 cially when it is required to operate on pieces of wood of large 

 dimensions, as, for instance, upon logs of two or tliree yards, or 

 even more in vvidth, and upon any diameter and size wliatever. It 

 will be seen, as I before said, that it can be applied at will to cut- 

 ting wood from a single piece into continuous and very large 

 slieets, as to cut wood from several narrow pieces into rectangular 

 sheets, proportioned to the size of the same pieces. 



16* 



