316 



THE CIVIL ENGINEER AND ARCHITECT'S JOURNAL. 



LOCTOBER. 



Bombay IMint were so much above Standard, thai if they may be assumed 

 as being fairly represented by 60 pyx assays made of tljeni at the Royal 

 Mint, and the value of the out-turn calculated thereby, they must have 

 contained very nearly 3G,000 rupees worth more pure silver tiian they 

 ouRht to have done ; a case in point showing the impossibility of tlie i\lint 

 ofliccrs guarding against loss, because if it b** assumed that the niHrchants 

 were fully paid for their bullion, the Miul must have sull'cred the loss of 

 the above sum. 



Witli rpfrard to the probability of loss of metal, the author 

 examines v^■hetlle^ it could take place in the mcltin;^:, and lie juen- 

 tions — 



There is a greater probability in this process, that a real loss, an 

 actual diminution of value should occur, than in any other. I have 

 above stated that a change of value cannot possibly be effected, except by 

 a liieral abstraction of the precious metal, and we can easily understand 

 why such is the case. If a pound of pure silver, for instance, were 

 melted a thousand times, and if copper were added to and subtracted from 

 it by successive portions: at every step of these processes, provided none 

 of the particles (if pure metal had been allowed to escape, the result of 

 every true assay of the metal, whether in its coarse or fine condiiion, ought 

 to be such as to make its value equal to that of a pound of pure silver. 

 There is nothing in mere manipulation to alter value, unless some of the 

 precious particles are dissipated; but we might be inclined to suspect 

 that this might occur during fusiou. It is not impossible, one would think, 

 that silver might be volatilized, and thus the precious metal be diminished 

 in quantity. It is certain that if any alloy be melted, its wi-ight after 

 fusiou is considerably reduced ; but it is also eqally certain that, practi- 

 cally, not a particle of silver escapes from the furnace. 



This being the only point on which the smallest doubt could reasonably 

 be eutertaiued, I have given it the most attentive examination. When 

 I was in Calcutta in January, 1842, aud visited the Mint there, I made 

 particular inquiries as to the volatilization of silver. The very idea of 

 such a thing seemed to be considered absurd, and I was assured that no 

 such thing as volalilizatiiui of silver had ever been experienced. It was 

 not the custom to swc p out the chimneys, because llie volatilization of 

 silver was out of the question, but I was told that vvhm that metal was 

 adulterated with mercury there was a loss, aud particles of the mercury 

 might be evaporated. This is true also iu regard to lead, fumes of which 

 escape from silver very frequently. But neither of these would at all 

 change the value of the mass iu fusion. 



The same questiou has also been practically tested at Madra.s — and 

 though uo such thing as sweeping the chimneys for the purpose of reco- 

 vering volatilized silver had ever been heard of previously, I determined 

 upon having it done, in order to obtain decisive evidence upon a point of 

 so ranch irn|)ortance. The result was, that in the chimney of a furnace 

 which had been in constant daily use for about 15 years, and in whi<'h 

 many crores of rupees worth of bullion must have been melted, there were 

 collected particles of silver which altogether weighed about 70 (/rains. 

 This experiment taken in connection with the experience of the Calcutta 

 Mint, seems to my mind to be quite conclusive as to the fact that there is 

 uo real loss iu nrelting, by any dissipation of the precious metal. 



The following is a practical explanation of one of the causes of 

 apparent loss : — 



It is notorious, however, that when silver is melted for coinage, the 

 weight after fusion is considerably less than before, even after making this 

 recovery and every allowance. It is admitted also that the metal under- 

 goes refinement, and consequently that it has become purer in quality than 

 it was. All that I wish to add is, that its value after fusion ought to be 

 precisely equal to what it was originally, and that there is uo necessary 

 cause for wastage or loss ; and this, because it is simply copper, and 

 nothing besides but copper, or base metal, which is injured by the heat, so as 

 to be separated from the alloy and lost in the refuse, whence it is not worth 

 while to recover it. It is owing to the absence of any means of recognis- 

 ing the miuule changes of fineness in the silver alloy, and the consequent 

 adoption of a system of account independent of them, that it has been im- 

 practicable to exhibit this truth, or to lake advantage of it, in the manner 

 indispensable to avoid waste ; and the alteution being therefore exclusively 

 paid to ihat change in the metal which alone is palpable, viz., in its weight, 

 IS one of the great causes of the real loss which 1 inquired into. I propose 

 hereafter to detail the means by which this evil has been rectified ; iu the 

 mean time 1 must invite attention to another. 



When ilie Mint receives bullion, it is supposed to receive nothing but 

 solid metal, which is charged to it according to its weiglit aud actual fine- 

 eess, but I found that tlicse supposed conditions did not always exist, and 

 that the bullion was not always made over to the Miut iu tlic solid stale. 

 In some cases coins were received, which were always mure or less dirty, 

 aud tliesi- were calculated in the accounts by multiplying the gross weight 

 of din and silver by the average fineness of a sample melted for assay. 

 'Jlie consequence manifestly was an unavoidaiile loss, corresponding 

 with the amount of dirt which had been reckoned as silver, and the 

 riniedy was plain, viz., taking care to melt the coius always in future. In 

 this way one of the principal causes of the previous loss was got rid of. 



Another case was more serious to the parties. 



We may also cite a case which occurred in Bombay, where there was 

 a deficiency between the produce and valuation of a pariicular parcel of 

 bullion received into the Mint, to the amount of about l,iOO rupees, A 



committee being appointed to inquire into the deficiency, stated, that the 

 discrepancy was apparent, but as it would never do to doubt the assays, 

 they must conclude the fr.iud had been practised by the melters. The 

 head melter was accordingly ordered to pay the money, and did so ; but 

 it was afterwards plainly shown that the valuation had been mude without 

 proper precautious agaiu&t mistake, and that iu so far as the evidence 

 went, there was not the least reason to believe that the quantity of bulliOD 

 for which the melter had been held accountable had ever beeu received by 

 him. 



In annealinp, an apparent increase of weight takes place, which 

 is thus explained. — 



The process of annealing is for the purpose of softening the blanks, 

 and making tlieui mure fit to receive the impression of the die. It also 

 assists the operation of the acid iu cleaning. Tlie blanks are placed 

 iu a reverberatory furnace and brought to a red heat, after which 

 they are cooled, either by inuuersion in water, or by exposure to the air. 

 Tlie effect of tills process is a slight increase of weiglit, owing to the com- 

 bination of oxygen with the alloy in the metal ; and as it is entirely super- 

 ficial, it varies iu its proportion according to the form and superficial area 

 of llie pieces exposed to its action. \\'e have uoi made any experiments 

 with minute atciiracy on this point, as the pieces after leaving the lami- 

 nating and adjusting department are counted on transfer, and thus passed 

 from baud to hand by tale, so lliat trifiiug variations in the gross weight 

 cease to be of any importance; but from the experiments which we have 

 made, the dilTereiice of weight in rupees has beeu shown to be about 

 3 annas 7^ pie per iiiille, or 4^ pie per cent. As this increase of weight is 

 occasioned merely by the addiiion of a foreign substance (oxygen) lo the 

 metal, it cannot of course, by any possibility, be the cause of any loss of 

 value. 



In blanching, a slight difference in the apparent weight takes 

 place, because in some mints grease and oil are used in laminates, 

 wiiich adlieres to the metal and is removed by the acid. 



Diifereiice of weight may take place, but difference of value 

 cannot ; and it is by adopting this latter test tiiat a proper system 

 of accounts can alone Ue adojited. We may remark, in conclu- 

 sion, that the author has laboured very hard and conscientiously 

 in establishing the correctness of his views ; and, whicli excites 

 the more admiration, as liaving been done under the liot sun of 

 Hindostan and in a state of ill-health. 



THE PLATE-GLASS TRADE. 



The statistics of the manufacture of pUte-glass iu Kngland, just published 

 in a tabular form, with a few remaiks appended, on a folio sheet, by Mr. 

 Henry Howard, of I'laistow, in Essex, are very instructive. 



In 1819 the excise duty on plate-glass was 98s. per cvvt. ; none was made 

 in England larger than 120 inches by 72, the quality was iuditferent ; the 

 price when 12 inches square was 13s. \d. per foot, when 120 inches by 72, 

 it was 160s. per foot. 



In 1827 the excise duty was 60s. per cwt. ; plate-glass 144 inches by 75, 

 was manufactured; the quality was considerably improved; the price of 

 plate-glass, when 12 inches square, was 6s. 8rf. per foot, when 114 inches by 

 75, it was 50s. per foot. 



In 1847 there was no excise duty on plate-glass; plates 144 inches by 76 

 were manufactured ; the quality was very much improved : the price of 

 plates 12 inches square was 3s. id. per foot ; plates 144 inches by 76, cost 

 3as. 6d. per foot. 



In 1819, when the •excise duty was 98s. per ewt., the quality of the glass 

 was indifferent, the average price per foot 20s. to 25s , the quantity sold per 

 week about 3,000 feet, and the supply apparently equal to the demand. 



In 1827, when the duty was 60s. per cwt., the quality was improved, the 

 average price i>er foot 10s. to 12s., the quantity sold per week about 5,000 

 feet, and the supply inadequate to the demand. 



In 1847, when the excise duty had been taken off, the quality was very 

 much improved, tlic average price per foot 4s. lo 5s., the quantity sold per 

 week about 70,000 feet, and the supply very inadequate to the demand. 



In 1836, when the excise duty was 60s. jier cwt., the estimated number 

 of hands directly and indirectly employea in the manufacture, was about 

 2,500, the ca|iital invested in it about 250,000/. 



In 1847, when the duty hud beeu taken off, the number of hands was 

 about 12,000, the capital aliout 1,000,000/. 



No comment is required on the tendency of these facts to show how much 

 the manufacture was benefitted by the reduction of excise duties; how much 

 more it has been benefitted by entire emaucipation from the trammels of the 

 excise. 



Since 1845 foreign plate-glass had been allowed to be imported free of 

 duty. In July 1847, Lord George Bentinck undertook to prove (in Par- 

 liament) that the removal of the glass duties had been a failure. He 

 stated that the declared value of glass exported in the first five months of 

 1845 was 215,630/.; in the first five months of 1840, only 131,739/. But 



