56 



THE CIVIL ENGINEER AND ARCHITECTS JOURNAL. 



[February, 



protect the metallic powilcrs or metal leaf, tlic lime, or other alkaline matter^ 

 which is adilcil to ihem (for the (mrpose of neutralizing the acid), must be 

 suhse<|iieiitly si'par.iled by fillration ; hut if any of the oils or varnishes 

 should not be sufliciently fluid to pass through a filler, they are made so, by 

 tlie .addition of spirits of turpentine, which is afterwards separated from them 

 by evaporation. 



The patentee claims, as his invention, firstly, a pigment or paint, consisting 

 of briulit metallic particles, combined with purified gums, oils, or spirits, in 

 such manner, and in such proi>i>rtions, as to form a painting fluid. Seiondly, 

 tlie method, hereinbefore described, of preparing a fluid for the purpose of 

 mixing with metallic particles or powder (known as bronze powder), and 

 forming thereby a pigment or paint. Thirdly, the combination of lime, or 

 other suitable alkaline matter, with such gold siie or varnish as may be uscrl 

 in fixing metallic powders and metal leaf. Fourthly, the use uf lime, or other 

 suitable alkaline matter, for the purpose of neutralizing the acid contained 

 in such turpentine, oil, or varnish, as may be used as a covering or protection 

 to metallic powders and metal leaf, and the means, hereinbefore described, of 

 effecting the same. 



IMPROVED STKAM BOILKR. 

 William F.mrb.\irn and John Hetih-.kinoton, of Manchester, Engineers, 

 {or " certain Improvimc-tils in stalionary aleam boilers, anil in the furnaces and 

 flues connected tlicrewith."—Giaiiled April 30; Enrolled October 30, 1844.— 

 ( With Engravings, Plate V.) 



The engravings Plate V. shows an ini\jroved boiler, by Mr. Fairbaiin of 

 Manchester, wherein is embodied many important (lualitics, both as regards 

 the economy of fuel, and what is almost of eijual import.ance, the prevention of 

 smoke. It is perfectly cylindrical, and contains two circular tubes or flues, 

 varyin^' from 2 ft. fi in. to 2 It. 9 in. diameter, which extends from the front 

 to the further extremity of the boiler. For a distance of 6 or 7 feet from tlie 

 front, the flues are made elliptical in order to receive the furnace and grate 

 bars, and to give room not only for space over the fire, but to increase the 

 capacity of the ash pit, and to admit a sufi^cient supply of air under the bars. 

 On this principle of construction, it will be observed that each furnace is sur- 

 rounded by water in every direction, and to prevent injury to the plates, the 

 water spaces are in no instance less than 5 to SJ inches wide. These water 

 spaces are of considerable value, as the flues from their curvilinear form recede 

 frcm each other at the line of the horizontal centres, and by these means the 

 water spaces are enlarged above and below the furnaces, and much greater 

 security afforded both as regards the durability and wear and tear of the 

 parts. 



Another advantage is the facility with which the sedimentary deposits 

 take place, and as these deposits are not immediately over the furnace, but 

 close to the discharge cock, where the temperature is lowest, it follows that 

 less risk is incurred, and greater security afforded than could possibly be at- 

 tained in the old construction. These advantages are peculiar to this con- 

 struction, and on reference to the engravings Plate V„ it will be seen that these 

 deposits can never be injurious, as exclusive of the cock, which is placed at the 

 lowest point in front, for discharging the sediment as it settles. There is in 

 addition a manhole for cleansing and thoroughly securing the interior as of- 

 ten as accumulation takes place. 



Another feature in this construction, is the perfectly cylindrical form of 

 every part, which (with the exception of the two furnaces being slightly 

 elliptic,) gives the strongest form, and thus ensures safety under any pres- 

 sure, not exceeding 401b. on the square inch. 



This appears to be a great improvement over the square and wagon shaped 

 boilers, which, with the same thickness of plale, cannot be worked with safety 

 above 10 lb., without the introduction of heavy stays to resist tlie pressure 

 and retain the boiler in shape. 



Objections h.ave been taken to the cylindrical boilers with internal furnace 

 and large single flue, as constructed in Cornwall. It has been alleged that 

 the boilers are insecure, from the small quantity of water which they contain ; 

 it is, however, well known that the security does not depend upon the cubical 

 contents of water contained in the boiler, but from the depth and area 

 of its surface over the flues. If for example a wagon boiler is taken (having 

 an interior flue,) 24 feet long, and (i ft. 6 in. wide at the water line, with 9 

 inches depth of writer over the flue; and again, if we contrast with this a 

 boiler of the circular form of equal evaporating powers, of the same dimen- 

 sions at the water line, and with equal depths of water over the flue, it is 

 evident that 'n case of neglect or injury to the feed pumps that the rate at 

 which the water will be reduced will be the same. This is easily proved by 

 the quantity of water evaporated, which in both cases, being equal to 

 24 " (3'5 X ■7.'J = 117 cubic feet. 117 cubic feet of water must, therefore be eva- 

 porated in both cases before the surface of the flues is uncovered. In fact 

 the only advantage gained even in this respect is, the wagon or square boiler 

 being less subjected to danger arising to the plates from the fire not being in 

 the flue, as the heat in this case is considerably reduced before it reaches that 

 iiatt, but this is more than compensated by the increased iiowcrs of evapora- 



tion, which are so strikingly exemplified in the circular boiler from the 

 rotundity of the flues, which in the event of accident or neglect expose much 

 less surface of dry plale to the action of the fire. 



As the evaporative powers of a boiler depend upon the quantity of fluesur- 

 face which it contains, we may probably venture in this place to trace the 

 comparative merits and peculiar advantages belonging to the old and new 

 forms. In this enquiry it is not cur intentinn to enter upon a strict analysis 

 of principles, but simply to enquire into facts, and by comparison to ascertain 

 the best and most economical form of construction. It is well known, prac- 

 tically and experimentally, that the evaporative powers of a boiler follow a 

 certain ratio as compared with the amount of flue surface exposed to the 

 action of the fire, and also as respects the relative area of grate bar surface 

 in evaporating a given quantity of water and producing a certain eflect 

 Now, if we take as the maximum quantity 12 square feet of flue, and 100 

 square inches of grate bar surface to the horse power, we shall then liave the 

 comparative values of the wagon boilers and that now under consideration. 



Taking boilers of the same dimensions as before, we shall have for the 

 wagon boiler 502 square feet of flue surface, and for the improved circular 

 boiler .529 feet. This gives an excess of 27 feet, which taken at 12 square 

 feet to the horse power gives 41'8 for the wagon, and 44 horse for the cylin- 

 drical boiler. But this is not the only advantage of the improved form, as 

 the position of tlie flues are much more favourable in the latter as an ab- 

 sorbent than in the former, where a great proportion or the whole of the side 

 flues are vertical, and in a less favourable position as recipients of heat. 



In this comparison it is assumed that the area of grate bar surface is the 

 same. Having stated this much, it will be necessary first to describe the 

 drawings, and subsequently to state the process by which tlie results already 

 noticed are obtained. 



Description.— TJi/crcHce to Engravings.— Y\^. 1 represents a plan and 

 longitudinal section of the boiler with double flues and double furnaces, 

 and figs. 2 and 3 a transverse section and end view. In these representa- 

 tions it will be seen that the gases emitted from the furnaces n, a x, 

 are conducted along the internal tubes into the return flue b ; from b they 

 cross under the boiler below the ash-pit into the flue c, and from tlience along 

 the opposite side of the boiler into the main flue d, which communicates with 

 the chimney. From this description it will be observed tiiat the gases do 

 not unite until they have reached e c, at the end of the boiler. At this point 

 a change immediately takes place in the gaseous products, and that from one 

 of two causes, as follows. Suppose the furnace o .r to be newly fired, and 

 the fuel in furnace a in a perfectly incandescent state, it then follows that the 

 gases passing from a will not only be different in their constituents to those 

 from o .r, but they are at a much higher temperature, and both furnaces 

 having received air as a constant quantity through the fixed apertures / f, it 

 will be seen that in the event of a surcharge of air on one side and a diminished 

 supply on the other that their extremes are neutralized by the excess of oxy- 

 gen, and the increased temperature which effects ignition at the point e, 

 w here combustion lakes place. All that is therefore necessary is to replenish 

 the fires alternately every 20 minutes, in order to eflect the combustion of 

 the gases without the least appearance of smoke. These, ami the increased 

 recipient surface, are the leading properties of this boiler, wliich compared 

 with others having single flues, is found to be greatly superior, either as re- 

 gards the combustion or the economy of fuel. 



BORING APPARATUS. 

 EonERtBEART, of Godmanchester, Huntingdonshire, gentleman, for " Im- 

 provements in apparatus for boring in the earth and in slone,'^ — Granted July 12, 

 1844; Enrolled Jan. 1845. 



This invention has for its object the so arranging of apparatus used when 

 boring in the earth and in stone, tiiat the parts cut or moved by the boring 

 tools may be constantly removed by a flow of water. It is well known that 

 when boring in the earth that the tools and apparatus employed are 

 constantly being raised, in order to bring up the soil or matters cut or 

 moved by the tools, w hich renders the practice of boring very expensive ; and 

 the inventor has discovered that in many cases he can employ a current of 

 water to bring up the soil or matters cut or moved by the tools, by which the 

 work of boring may be carried on for a great length of time without lifting 

 the apparatus and tools, and the only cases in which his invention is not ap- 

 plicable are where the soilthrougli which the boring is desired to take place 

 w ill not retain water, so as to allow of a constant current being kept to flow 

 upwards in the boring: for this purpose the patentee has an apparatus for 

 boring in the earth. An excavation is first dug, which during the boring is 

 kept constantly full of water, the boring is made by any suitable tool fixed at 

 the lower end of a tube acting as the bar for giving rotary motion to the tool, 

 and at the same time it acts as one of the limbs of a syphon, through which 

 there will be caused a constant lising current of water to cany up the soil 

 and matters cut or moved by the tool below. The tube is made sipiare, on 

 the outer surface a bar is fixed at any part, by which manual or other power 

 may he applied to turn it. The tube is composed of many pieces, which are 



