1847.J 



THE CIVIL ENGINEER AND ARCHITECPS JOURNAL. 



193 



flat or of any other form ; after it is silvered it is washed, to remove the 

 impurities which have been deposited with the silver, and then placed in a 

 hot-air closet, where it remains for a few hours until perfectly dry ; it is 

 then varnished, to protect it from the action of the air, and also from being 

 scratched. Glasses of any dimensions may be silvered in the most perfect 

 manner in 48 hours. The silver deposited by this process adheres more 

 firmly than does that by Ihe old method; it is also less injurious to the 

 health of the workman, as mercury is not used ; and the cost of produc- 

 tion is not increased." 



Mr. WiNKwoRTH stated that he considered the invention as one of the 

 most beautiful and most valuable of the present day, as the silvering can 

 be applied to any surface without difficulty. 



Mr. Newton observed, that as it is a solution of silver that is used, 

 there is no olher method of obtaining such line particles ; the adhesion is 

 firmer, the use of mercury is dispensed with, and the whole process is 

 completed without increase of cost. 



2. By Mr. Brett, " On his Electric Printing Telegraph." The appara- 

 tus was exhibited.— The author commenced by stating, that in July, 1845, 

 he endeavoured to introduce to the government his printing telegraph, and 

 to urge on them the importance of adopting some such plan as his, in the 

 place of Ihe semaphore. The great advantages of the electric printing 

 telegraph, either for government or other purposes, are its great simplicity, 

 certainly of action, and economy. The instrument consists of two parts ; 

 one having a row of ivory keys, with the letters of the alphabet, words, 

 or other characters, marked upon them, and is connected with one end of 

 the telegraphic wire, the other end being connected with the printing ma- 

 chine. The printing machine contains a type-wheel, having on its circum- 

 ference corresponding letters, words, or signs with the key-board, and by 

 means of weight movements and an escapement, a very slight power is 

 sufficient to regulate the whole; so that the instant a key, representing 

 any letter, &c., is pressed down, the corresponding letter, &c., is printed 

 and a bell rung at the other end of the instrument. 



IMr. Brett staled that he considered the advantages of his instrument to 

 consist in its making a permanent register of the communication transmit- 

 ted, it being printed on paper supplied from a roll of unlimited lengtii, 

 from which any portion of the correspondence may be cut off at pleasure. 



3. By Mr. F. AVhishaw, " On the application of Heated Currents to 

 Manufacturing and other purposes," — " In November, 1844, (says Mr. Wms- 

 ham) I read a paper on the manufacture of casks, more particularly those 

 used by brewers, with remarks on the various methods adopted for cleans- 

 ing and purifying such vessels. The object of the present paper is to show 

 the advantages arising from the application of the same patent, viz., that 

 of currents of heated air to the following purposes: — 1. Seasoning timber 

 generally. 2. Preserving timber. 3. Purifying feathers, blankets, cloth- 

 ing, &c. 4. Drying coffee. 5. Roasting coffee. G. Japanning leather 

 for table covers, and other purposes. 7. Drying silks. 8. Drying yarn. 

 9. Drying distillers' tuns. 10. Drying papier mache. 11. Drying vul- 

 canized India rubber. The process has also been successfully tested for 

 the following purposes: — 12. Drying loaf sugar. 13. Drying printing 

 paper, or setting the ink to enable books to be bound more quickly than 

 usual. 14. Drying starch, and converting it into dextrine or British gum, 

 and also, 15, for preserving meal." The paper then proceeded with a very 

 lengthened account of the action of heated air on the variouskinds of timber, 

 and the success which had attended its adaptation for that purpose. It was 

 also staled that sixty suits of clothes, which had belonged to persons who 

 had died of the plague in Syria, had been subjected to the process of puri- 

 fication, at a temperature of about 240 degs., and afterwards worn by sixty 

 persons, not one of whom ever gave the slighlestsymptoms of being affected 

 by the malady. The author concluded by referring to the mode adopted by 

 the North American Indians, for preserving the flesh of the buffalo, viz., 

 that of drying it in the sun, and stated that healed currents had been ap- 

 plied successfully. " How important for shipping? Instead of sailors 

 consuming salted provision from one month's end to another, to have an 

 occasional supply of fresh meat." It is important also in other respects, 

 as meat treated in this way occupies much less space, and is much lighter 

 in weight. It is believed that the juices of the meat contain about |ihs of 

 watery moisture ; this the current of heated air removes, and leaves the 

 albumen, and all the flavour and nutrition behind. 



May 5. — Sir John Boilead, Bart., V.P., in the Chair. 



1. By Mr. Defries, " On his new Patent {5rd) Dry Gas Meter. " — It 

 is notorious, observes Mr. Defries, that the gas supplied by some London 

 and provincial companies, contains sulphuretted hydrogen and ammonia, 

 and these lend to impair the gas meters and prevent correct registration. 

 The object of the present invention has been to place the more delicate and 

 ■working parts of the meter beyond the reach of the gas and its injurious 

 action; and has been accomplished in the following manner — viz.: by 

 shutting of the machinery in the upper chamber of the meter, by means of 

 a rotary airtight valve, which allows the gas to pass from the main to the 

 meter, and from the meter to the supply pipe, without even coming in con- 

 tact with the vital parts of the machine. The valve and gearage are also 

 made of an amalgam of metal, upon which the ammonia and sulphur of 

 the gas do not act. Gas meters on the old and new principles were exhi- 

 bited, as well as numerous specimens of the metals, which had been ren- 

 dered useless from the action of the impure gas. 



Mr. Newton said, he did not consider Mr. Defries entitled to the merit 



of the invention of the rotary valve, as it had already been patented by 

 Messrs. Edge and Wright. 



Mr. Wkicht was present, and exhibited one of his valves. He also 

 stated that Mr. Defries' meter had still about twelve of the working parts 

 exposed to the action of the gas. 



Mr. Defries, in reply, stated that he was quite aware that the rotary 

 valve had been previously patented by Messrs. Edge and Wright ; but 

 there was this difference between his and theirs— viz., that theirs was a 

 Ihree-throat valve, and does not shut the gas off from any part of the 

 works, while his is a six-throat valve, and excludes the gas from all the 

 more delicate parts of the machine. 



2. ByMr. T. Boccius, '^ On his improved Gas-burner." — The two most 

 important points in the combustion of gas, are economy and perfect light; 

 " and these desideratum combiued, I believe I have attained," says Mr. 

 Boccius, '• with my burners." The patent for the present burner was 

 taken out in 1843 ; and the burner is so constructed as to admit such an 

 amount of atmospheric air as will completely oxygenate the burning 

 hydro-carbon, at the same time keep up the same amount of intense heat, 

 even to the apex of the flame, which is necessary to the incandescence of 

 the solid carbon, in order to obtain luminosity. 



" In the patent of 1843, (Mr. Boccius says) I did not confine myself to 

 any given form of burner, as my apparatus can be adapted to all forms, 

 whether flat, half-circular, triangular, circular. Sec, the result always 

 being the same." 



It consists of a series of concentric rings, from the centre of which rises 

 a crescent-formed tube, with olher coucentric rings. These latter serve to 

 keep up the required heat at the apex of the flame, and also to steady the 

 light. From the form of burner, it is shadowless, no portion of the light 

 being obstructed either above or below the flame. 



Mr. Newton and Mr. Roberts then alluded to Ihe tulip-shaped burner, 

 for which a patent had been taken out, that particular form being given to 

 the flame by means of a current of air passing through a perforated button 

 or inverted cone, into the body of the flame. 



Mr. Boccius stated that the inverted cone was included in his patent ; 

 that no action took place from the passage of air, as stated, the flame 

 being expanded more or less, according to the height at which the cone is 

 placed in or from the flame. 



The Secretary described " An Excavating Machine," by Mr. Pri- 

 DEAiix. (See Journal for July last, page 219.) The machine consists 

 of a series of scoops attached to arms fixed on an axle driven by a steam- 

 engine. As the scoops revolve, they slice off the earth, and discharge it 

 on to an inclined plane, on which it is removed to the wagon. The whole 

 apparatus bears a resemblance to the ordinary dredgiog-machine, and is 

 worked by a steam-engine. 



Mr. W. E. Newton stated that an American machine, for a similar 

 purpose, had been used on a railway at Brentwood, and succeeded very 

 well. It cut some millions of tons of earth away in the United States. 

 The greatest difficulty they met with, was getting the wagons up to, and 

 away from, the machine. 



Mr. Prideaux stated that two wagons could be brought up at one 

 time, and there would be no difficulty in changing them as fast as the 

 machine tould fill them. 



RBVIE'WS. 



Practical Observations on the Present Slate of tie Steam Engine. 

 By G. V. GusTAFSSON, late engineer R.N. London: George Her- 

 bert. 



Mr. Gustafsson's work is a small pamphlet of 36 pages — the purport 

 of it seems to be to show that much power is lost in the present ex- 

 isting forms of marine steam engines; as a substitute for which the 

 author proposes an improvement, or rather modification, of his own. 

 The most valuable part of his treatise is a table of the rates of motion 

 of the steamer Acheron, and of the angular velocity and extent of im- 

 mersion of her paddle-wheels — the result of experiments instituted 

 during the three years that Mr, Gustafsson was her acting engineer. 

 This alone, as furnishing very useful and important data for subsequent 

 investigations, we consider a sufficient recommendation of the work 

 to the notice of our practical readers ; although we must at the same 

 time caution them against adopting the author's mechanical views— 

 which, in statement at least, if not in conception, appear to us ex- 

 tremely confused. The reasons assigned for the frequent occurrence 

 of breakage in the various parts of marine engines, exhibit the too 

 common incorrectness of thought concerning pressure and impact 

 which is constantly displayed by men not thoroughly versed ia 

 the principles of mechanics. The casualties above alluded to are 

 easily explained, and are not at all owing to any peculiar mode of con- 

 struction in the engines. Marine engines are especially subject to 

 impulsive strains, the amount of which is not easy to calculate before 

 hand ; they have no relation whatever to the horse power, or any- 

 thing of the kind, but are chiefly caused by heavy seas breaking 



