1946.1 



THE CIVIL ENGINEER AND ARCHITECTS JOURNAL. 



189 



tint the air here contained * certain qnantity of sulphuric acid, arising from 

 the combustion of coal ; the quantity of the acid was, however, 30 small, 

 that it was difficult to detect it by chemical analysis. He had enquired of 

 several excellent chemists, but they were unable to state what effect the sul- 

 phuric acid in the atmosphere had upon building materials. 



Mr. Godwin alluded to the necessity of seeing that work of every kind 

 was perfectly dry before the cement was laid on. He had recently had oc- 

 casion to use Jardan's cement, and had, as he thought, used sufficient pre- 

 caution in waiting till the work was dry. Owing, however, to the slight 

 quantity of moisture which it retained, the plaster all fell off. 



Mr. TiTB observed, that all cements of this class, beginning with mastic, 

 were, chemically speaking, nothing more than very coarse paints, mixed up 

 with oil or grease. The disadvantages attending this class of compositions 

 wa« that the sun and wind dissipated the fatty matter or oil with which they 

 were combined, and the cement soon decayed. The Portland-stone cement, 

 which was, in fact, the hydraulic cement of the French, was an excellent 

 material, and was in almost universal use in France. It was absolutely ne- 

 cessary that this material should be mixed with a certain proportion of clay: 

 it was also of the greatest importance that after it had once been " gauged," 

 it should never be disturbed or touched till it was thoroughly hardened. 

 Unless this precaution were strictly observed, the permanence of the work 

 could never be ensured. It was also a good rule that were patent cements 

 were used, the patentees should be required to use it with their own work- 

 men, and not with strangers, who were ignorant of its nature. 



Mr. PoTNTER referred to the use which Mr. Nash had made of the oily 

 cements in his own house in Regent-street, as a proof of the disadvantages 

 to which those compositions were liable. It might be supposed that the 

 cement being applied to the architect's own house, the work would be done 

 in the best manner possible. It was found, however, that the oil soon fried 

 out, and the surface became discoloured with the well-known stains resem- 

 bling the lines in maps. 



Mr. TiTE remarked that the Portland-stone cement was, in fact, an artificial 

 imitation of the nodules of lime, from which Roman cement is prepared. 

 The nodules are found in great abundance on the coast near Harwich. 

 They fall from the cliffs, in which they are imbedded, on to the beach, and 

 are there picked up. They are compact masses of carbonate of lime con- 

 taining a small quantity of iron, to which latter substance they owe their 

 dark brown colour. The chatix hi/draulique was precisely the same sub- 

 stance, without the colour derived from the iron. He thought, however, 

 that the iron added materially to the strength of the cement when hard- 

 ened, and that for this reason the Roman cement would never be equalled in 

 strength by any artificial composition. Atkinson's cement was made of 

 nodnlee in which the iron was not present; the advantage of this and the 

 hydraulic lime was, that they naturally possessed a good colour and did not 

 require painting. 



SOCIETY OF ARTS, LONDON. 

 Jpril 29.— W. F. CooKE, Esq., V.P., in the Chair. 



The first communication was " On Mr. Godson's Patent Furnace for con- 

 turning smoke and economising Jiiel." By W. Spence, Esq. The general 

 features of the furnace and the parts of which it is composed uiay be tnus 

 described : — A box with a moveable bottom, or feed-plate for the fuel, and 

 fitting its internal surface, is substituted for the ordinary bars in the middle 

 of the furnace, and is capable of being raised or lowered within the box or 

 chamber, and which is made to occupy a position in the ash-pit below the 

 furnace. The fuel is fed on the plate while in its lowered position ; and 

 when raised it is introduced into the centre of the fire, by which means the 

 smoke evolved from the fresh fuel is consumed. In order, however, to ren- 

 der such a mode of supplying fuel available for its purpose, it is necessary 

 that at the time when the feed-plate in the centre of the furnace is to be 

 lowered to receive its charge, the portion of burning fuel resting thereon 

 should be supported : for this purpose two plates of metal are made to enter 

 the furnace, one on each side, and meet in the centre. Again, it is requisite 

 for the due promotion of the draft into the furnace, that inasmuch as the 

 centre support of the fuel consists of a dead plate, that plate should be kept 

 a little below the fire bars, and that a series of oblique bars should be 

 formed, and extend from the ordinary fire bars to the plate. A model and 

 diagrams of the invention were exhibited, and a lengthened discussion took 

 place as to its merits. 



The second communication was " On a Machine to Register the Velocily 

 Iff Railway Trains when in motion," by M. Ric.\rdo, Esq. The machine 

 consists of two parts : one receives motion from the carriage, the other by 

 clock-work. They are arranged in the following manner ; — an excentric is 

 placed on the axle of the carriage, and gives motion, by means of a con- 

 necting rod, to a lever atladied to the machine, which lever acts upon a 

 ratchet wheel, and is so arranged that each revolution of the wheel of the 

 carriage advances the ratchet one tooth. An endless screw is turned on the 

 spindle of the ratchet wheel, and gives motion to a small toothed-wheel 

 telow, and on the spindle of which is fixed what may be termed a lateral 

 ticcntric (as one part projects more than the other on the side of the wheeJ). 

 Against this the short end of a horizontal lever is pressed, by means of a 

 ipting. As the excentric revolves from the projecting to the lower part, it 

 moves the lever, and with it a pencil fixed at its other end, in one direction, 

 till it reaches the lowest point ; when, by a spring pressing upon it, it lakes 



the opposite direction, till It reaches the" highest point, when it returns 

 again. The wheels are so arranged, that the excentric makes one revolution 

 in each mile that a train travels. The clock-work is used to turn a drum, 

 upon which a ruled paper is wound. When the train is stopping at a sta- 

 tion, the pencil is stationary, and marks only a straight line; but when in 

 motion, diagonal lines are drawn by the action of the lever as described. 

 The extreme distance between the two points of the diagonal lines deter- 

 mines the velocity at which the train has been travelling. Thus, the train is 

 made, by this apparatus, to keep a perfect register of the work done, which 

 would at all times indicate the neglect of either the engineer or conductor. 

 Mag 6. — Thomas Websteh, Esq., M.A., V.P., in the Chair. 

 The following communications were read : — 



1. On an Improved Poppet Head/or Turners, by W. E\ekett, Esq. The 

 first attempt at improving the poppet head (observes Mr. Everett) was to 

 take off the point and insert a screw carrying a spindle and wheel fitted up 

 as a drill, to be driven by the overhead motion, and this he found to answer 

 very well when the hole to be drilled could be brought in a line with the 

 drill. Having done this he still anticipated that he could make this partjf 

 the lathe more useful, in fact a substitute in a great measure for the slide 

 rest. The following motions have therefore been given to the point. Ist. 

 An upward and downward motion so that it can be applied to all lathes. 2d. 

 A circular motion which enables it to be applied at any required angle ; and 

 3rd, a motion directly across the mandril, and there is no motion but what 

 is strictly mechanical, as each has a scale to guide the workman in its use. 

 Several gentlemen present examined the instrument and its arrangements 

 and considered it likely to prove a valuable addition to the ordinary lathe. 



2. On the Ventilation of Buildings. By Mr. A. J. Greex. — The paper com- 

 menced with an account of the various plans which the author adopted for 

 the purpose of ventilating the sick ward and other rooms of the Sudbury 

 Union Workhouse, and it then proceeded to point out the way in which he 

 would propose that all large buildings about to be erected should be built. 

 Where a double chimney is to be erected, he proposes that two air flues 

 should be carried up in the stack as near the centre as they can be got. If 

 the chimneys are not in the centre of the side or end of the room, the flues 

 should be carried so as bring them as nearly into that position as possible. 

 The flues need not he more than 14 inches by or 7 inches, or 9 inches by 

 9 inches, and should be commenced from the first floor and continued 

 through every successive story to the top of the chimney, in the same way 

 as the flues for the smoke. One flue of the above size would be sufficient to 

 ventilate four or five stories, if each room required it — valves would require 

 to be fixed in the wall or ceiling in connection with the flue. This system 

 of ventilation, he considers, would be very applicable to smoking rooms, tap 

 rooms, eating houses, or any buildings where a large number of persons as- 

 semble. 



3. On. the Concentrated Gravy of Meat. By Mr. Warriner. — This arti- 

 cle is manufactured at Sydney, New South M'ales, from the carcases of oxen 

 and sheep, which are bred there for the sake of their tallow, wool, hides and 

 bones. The value of oxen in Australia is from 15s. to 20s., and of sheep 

 Is. 6(/. to 2s. 6d. each. During the last year the leg bones of upwards o£ 

 109,000 oxen were sent over to this country, the greater part of the flesh of 

 tne anima.s oaving oeen nrown away. Ihe object of the present manufac- 

 ture is to render down the lean of the carcase into a solid portable soup, by 

 stewing it down in its own gravy, without water, in double pans ; by re- 

 ducing it in this way the water in the lov er pan prevents the fire passing 

 through, and giving to the soup the burnt flavour which it has always hitherto 

 had. When manufactured it is sold in cakes of various sizes, at the rate of 

 2s. per lb. One pound of the soup is said to be equal to 24 lb. of the best 

 gravy beef. 



CHEMICAL SOCIETY. 



April 20. — A paper was read by Messrs. Joule and Playfair, " On the 

 maximum density of water." In this the authors contended that the point 

 of maximum density is the proper standard at which waler should be taken 

 as unity for the purpose of comparing specific gravities. There are two 

 methods for determiuing the point of maximum density of waler; one of 

 these being the comparison of water in its expansion with that Of some 

 other substance the expansion of which had been already determined ; the 

 other virtually consists in weighing water in water, and was pursued by 

 Hope iu his original researches on this point. The authors adopted the 

 latter method as the one most likely to yield correct results, but altered the 

 method of experimenting, and the nature of the apparatus employed. 

 Their apparatus consisted of two vessels connected at the bottom by a 

 pipe with a cock, above by an open canal. One of these vessels was made 

 to contain waler at a temperature decidedly below that of the raaximum 

 density, the other being above that temperalure. On opening the stopcock, 

 a current took place from the colder vessel to the hotter, until a certain 

 time, when Ihe current became reversed. The rapidity and direclioo of 

 the current was determined by hollow glass beads. The experiment was 

 tried under varj log condiiions; and, as a mean of several series of experi- 

 ments, the authors fixed 39- 101° Falir. as the point of maximum density, 

 stating ihat Ihey believed ihis 10 be within -^th of a degree of the Irulh; 

 at all events, that it could nut be ^'j,ih of a degree in error. 



