206 



THE CIVIL ENGINEER AND ARCHITECT'S JOURNAL. 



[May 



three it contains plates of two buildings at Venice, the Procuratie 

 Nuove and the Library of St. Mark, the hUter the work of Sansovmo. 

 These are undoubtedly designs of great merit, and though having 

 mmv technical defects, undoubtedly showing much taste, and had they 

 ten times as m^ny faults we should prefer them to the insipid and 

 mindless copies of our modern architects. , t%- j 



It has struck us in looking at this valuable work that as M. Didot 

 has given English letter-press and English titles to the pUites, it 

 would increase their value much if a scale of English feet were in- 

 scribed in addition to the one of French metres. 



STAINED GLASS EXHIBITION. 



SiR,_The Stained Glass Exhibition as a national exhibition is cer- 

 tainly'disgraceful— but still it is what any person acquainted with the 

 circumstances attending the art of painting on glass might expect, for 

 it is the only branch connected with the arts which has not a fair 

 chance of advancement. In the first place, the orders which are given 

 are generally given to shopkeepers, who will only employ men who 

 wiil work cheap, for they expect to get four and 6ve hundred per cent. 

 Drofit on the works, consequently they must be badly executed to 

 enable the artist to exist at all ; and what is very strange, the architects 

 encourage the ancient stvle of glass painting; not the best examples, 

 but the worst absurdities of the ancients, abounding in nondescript 

 heads and animals in the bad drawing of the 12th and 14th century ; as 

 for instance, in the Temple and Savoy Churches : if men in those re- 

 mote periods could have drawn better they certainly would have done 

 so If you attempt to do better in the way of drawing, Sec, many ol 

 the architects say it is too good for glass, which I think is very ridi- 

 culous for it forces the artist to make his figures cripples to please 

 them— they speak of the colours used by WiUement and others 

 who know nothing of the practical part of the business. Mr. WiUe- 

 ment has at present two glass painters at work, who are reputed to be 

 the worst workmen in the trade, while the work of those two men 

 employs twelve glaziers to work up. So much for the artist s part ot 

 the work ; with respect to the colours, upon which they pride them- 

 selves if you will take the trouble to walk round the Exhibition, you 

 will find that all the glass painters have the same colours in common ; 

 —the colours are an article manufactured by the glass maker, and sold 

 at a certain price per foot to the trade ; therefore, no merit is due to 

 the glass painter, as he does not produce them himself, but merely 

 paints on the surface with brown and passes it through the hre to hs 

 that colour, which is the ancient principle. The modem style is to pro- 

 duce all the colours on one piece of glass, without the assistance ot 

 lead, which requires great experience in the glass painter to attain, 

 and is the only way in which a perfect representation of Nature can 

 be obtained; by having the real light shining through vour picture, 

 vou may obtain effects which no other style canaccomplish. But to 

 return to the Exhibition— I certainly do not think it right that trades- 

 people should be allowed to send in specimens of painted glass, as it 

 they were the artists ; if so, the Commission is rendered useless— lor 

 instance, Cobbet & Son are glaziers. Chance & Co. glass manufactu- 

 rers, Grace & Co. paoer haiigeis, and, Mr. Wailes a grocer at Newcas- 

 tle-on-Tyne, who has turned glass painter, and is filling our churches 

 with his ancient rubbish wholesale, introducing plenty of briglit colours 

 and figures with vellow faces as if they had the jaundice, as may be 

 seen in the figure'of the Pilgrim on the staircase at the Exhibition. 

 I am, Sir, your obedient servant. 

 May, 1844. W. N. 



considered as probable that the reducing agent in this process is alde- 

 hyde, formed from the alcohol by the agency of the oils employed. 

 It has been previously noticed that aldehyde will reduce silver from 

 its solutions, and indeed a solution of this metal has been proposed by 

 Liebig as the most delicate test for the presence of aldehyde in a 

 liquid. This explanation we believe to be correct; for if we examine 

 the composition of oil of cloves, as given by Dumas, it seems very 

 probable that it would reduce the ether of the alcohol to the state of 

 aldehyde ; for one proportion of oil of cloves and one of ether, are 

 exactly equal to six proportions of aldehyde minus water : thus 

 Oil of cloves =:C=°H'=0 = 

 Ether . =£JJ112. 

 QC--* H"0° 

 C *H =0 

 which, with one of water, forms aldeliyde, or, when oxide of silver is 

 present, reduces it by abstracting its oxygen, the aldehyde being con- 

 verted into aldehydic acid combines with another portion of the 

 silver present. 



It might be imagined that silver being the metal used, instead of, 

 as at present, the cheaper alloy of mercury and tin, the expense of 

 this process would prevent its extensive use ; but when it is known 

 that 12 grains of silver are sufficient to cover thoroughly a square foot 

 of glass (as stated by Mr. Warington), that there is no pressure em- 

 ployed, and therefore no risk of breakage, that the operation can be 

 carried on any where, no expensive level tables being needed, that it 

 is performed very cjuicklv, half an hour being sufficient to complete it, 

 and that when done:, there is no chance of its running, or crystallizing, 

 which is frequently the case with the present method, besides its far 

 superior brilliancy, we think there can be no doubt of its general 

 adoption. 



NEW PROCESS OF SILVERING GLASS. 

 At a recent meeting of the Chemical Society, Mr. Warington, the 

 secretary, gave a description of Mr. Drayton's patent process of sil- 

 verine crlass, and exhibited a beautiful specimen. The method em- 

 ployed °s, to add to a solution of nitrate of silver, sufljcient ammonia 

 to precipitate a little oxide of silver to the solution thus formed, to add 

 some oil of cassia mixed with spirits of wine ; this forms the silver 

 solution, which must be poured over the surface of the glass to be 

 silvered, and which must be previously well cleaned, a tllet ot putty 

 having been laid round the edge to retain the liquid ; on to the sur- 

 face of this must now be dropped a small quantity of the reducing 

 solution, which consists of oil of cloves dissolved in spirits ot wine, 

 when the reduction of the silver will take place, it being deposited on 

 the glass, the surface next to the glass assuming a splendidly brilliant 

 face, more resembling a pohshed speculum than an ordinary mirror. 

 In the course of the interesting conversation which ensued, i t was 



BEALE'S ROTARY ENGINE. 



Mil. Editor — Some time ago you gave a drawing of Beale's Patent Engine 

 and Boiler, now I shall feel greatly obliged if you could give or procure a 

 candid reply to ray questions, (. e., is the boiler a good or bad one — are the 

 tubes (above the water line) dangerous and liable to burn out or crack, and 

 does not the boiler piime very much ? The engine (though simple) of course 

 is bad, like all other rotaries, as it wears itself more at the periphery than at 

 the centre on the sides. I am exceeding pleased witli the information about 

 boilers, for it is a subject very much neglected, and is in my opinion of as 

 much consequence as the engine. Mr. Buck's article on tubes is good, but 

 nothing is said about the length, and therefore it is incomplete ; he would 

 find 3 in. tubes in a locomotive of the present construction very extravagant 

 of fuel, which is the main point in all boilers. You say plenty about marine 

 engines, but nothing about boats, which is worse than engines without boilers ; 

 could you not give the lines of some of the fastest river boats with full parti- 

 culars,' commencing with the boat, then the boilers, then engines, paddles 

 and speed. Such information would be very acceptable. 

 Youi's, respectfully. 



Patience. 



Birmingham, April 11, 1844. 



[We gave a drawing and description of Mr. Beale's engine and boiler in 

 the Mirnal, vol. 5, pp. ISl and 182, and if our correspondent wdl refer 

 thereto, he will perceive that we then noted the exposure of the upper ends 

 of the tubes to the fire as a great objection, as so much surface was lost. In 

 practice the water is kept nearly up to the top cock. Although we had a 

 somewhat lengthv trial with the boat and engines, we did not experience any 

 inconvenience from "priming;" this description of engme would not be 

 effected thereby in the same manner as a common reciprocating one. VVe 

 believe Beale's engine to be the best of aU the rotaries ; at any rate, the best 

 that has come practically under our notice. Its power is very great and con- 

 stant— the generality of rotaries are mere toys, incapable of heavy work. J 

 Editor. 



ROYAL INSTITUTE OF BRITISH ARCHITECTS. 

 April 29.— Mr. C. H. Smith on the Magnesian limestone.— Tais paper 

 was a continuation of those formerly read treating on the sandstones and 

 oolites : on the present occasion Mr. Smith proceeded with the subject by 

 describing the great beds of magnesian limestone, which he, with ittle m- 

 tervals, from Nottingham and Tynemouth,and more especia ly those between 

 Mansfield to Knaresborough, an extent of about seventy miles. In this dis- 

 trict stone is found combining the carbonate of Ume and magnesia from the 

 lowest amount of the latter to proportions comprising pure dolomite— ol 

 course they vary greatly, both in appearance and quahty, and that even in 

 cases where the substances are, chemically speaking, the same ;-among the 

 best of these stones, as building materials, are the Bolsoyer, Roche Abbey, 

 Barnham Moor, and Huddlestone. The first-named has been tested m the 

 Norman Church at Southwell, which remains in a state of high preservation ; 



