382 



THE CIVIL ENGINEER AND ARCHITECT'S JOURNAL. 



[November, 



are extremely desirous to adopt these as well as other European improve- 

 ments ; and it appears extraordinary that, in the depressed state of the iron 

 trade at home, capitalists have not been found to supply the requisite num- 

 ber of steam tugs and flat-bottomed vessels of iron fitted for navigating these 

 rivers in all seasons of the year, as well as for manufacturing machinery, 

 which is at all times in demand. For it must be borne in mind that, although 

 India possesses some of the richest iron mines in the world, she has neither 

 miners to work them, nor foundries to manufacture the prepared material ; 

 it is, therefore, to England alone she must of necessity look for her supply of 

 machinery and wrought iron. 



The extent of traffic on the Indus is not so much known to us. Dr. Burns, 

 speaking of the advantages of opening a commercial intercourse with Scinde 

 proper, says, " Although the miserable poverty of the people of Scinde for- 

 bids the hope of mercantile interchanges to any extent with them, yet the 

 natural advantages of the country for commerce need scarcely be pointed out ; 

 security to trade and property is alone required to render the Indus the 

 medium of introducing our manufactures among vast nations, which, occu- 

 pying climates resembling our native land, would gladly welcome the pro- 

 ducts of British industry, and offer to the speculations of our ingenious and 

 enterprising countrymen ample encouragement and reward." In the preface 

 to his interesting narrative he observes, "In the end of 1835. Messrs. Med- 

 dle and Wood had the gratification of exhibiting to the astonished natives of 

 Hydrabad the first steam boat that ever entered the Indus. Vessels laden 

 with rich wares from Bombay and Moultan. have now hailed each other on 

 1s waters, and while bazaars of Western India ale already teeming with the 

 shawls of Cashmere, and the products of the Punjaub. received by the long 

 forbidden route, not only for private speculators, but in large investments 

 rom Maharaja Runjeet Singh himself." 



There is abundance of coal in the several districts of Bengal, and in lieu 

 of coal, on the banks of the Indus, the •' jew ur," a species of wood abounds, 

 which, in the absence of coal, is found to be an excellent substitute ; there is 

 little doubt that coal will eventually be found in some of the extensive valleys 

 of this river. 



An estimate of the expense of steam boats tells us that each iron steam 

 boat, with engines of 100 ii.r. including freight from England, and expencis 

 of putting together in Calcutta, with wood work complete, costs £12,000 ; an 

 iron flat (accommodation boat) capable of carrying 100 tons of goods and 30 

 passengers. £3000; the total expense being ,£l. r >,000; the profits may be 

 fairly estimated at 20 per cent. 



It is to be hoped that the rivers of India, like those of America, will, jn a 

 few fleeting years, abound with these most useful auxiliaries to man's happi- 

 ness ; and that with increased facilities of communication, corresponding im- 

 provements will take place in the cultivation and manufacture of the staple 

 commodities of this country. Articles, such as cotton and sugar, which to us 

 haw now become essential necessaries of life, and for the supplies of which 

 we have at present to depend upon foreigners, are but little valued at home 

 in comparison to the same kinds of produce coming from foreign countries, 

 simply because due attention has not been paid to their culture and manufac- 

 ture ; and although some slight efforts have been made by the East India 

 directors to introduce a better order of things, and some few Europeans have 

 embarked their capital for the same laudable purpose, yet, comparatively 

 speaking, little or nothing has been done; , lor much until 



the means of communication from one pari i thil I i 1 continent to the other 

 have become more extended — until many of the fine old, ancient roads are 

 reopened and new roads are formed— until aqueducts, viaducts, and bridges 

 are built, steam boats crowd the broad, expansive rivers, mines are opened, 

 and foundries and factories are erected : all these objects may be gradually 

 attained by the employment of British talent, capital, and enterprise, thereby 

 increasing our own riches and prosperity, and at the same time administering 

 more immediately to the wants and desires of 150,000,000 of inhabitants of 

 India, who, as fellow-subjects, have a right to demand thus much otthe inha- 

 bitants of Great Britain— of that country which, for two centuries past, has 

 used its wealth, and diminished its internal resi 



TO PREVENT DAMP PENETRATING THROUGH WALLS. 



Some distinguished French chemists have lately directed their attention to 

 the means of excluding damp from the internal surface of walls. The fol- 

 lowing is a translation of some observations on the subject by M. M. Tlu'- 

 nard and D'Arcet. The experiments made by them were begun in 1813, 

 when M. Gros undertook to paint the cupola of the church of St. Genevieve 

 (then called the Pantheon). "The surface of the cupola had been previ- 

 ously prepared like a primed cloth : after the stone had received a coat of 

 strong size, a ground of white lead and drying oil had been superadded.'" 

 Fearing that this priming was not sufficiently firm, M. Gros came to consult 

 us. We did not hesitate to say it was far from safe. The moisture might 



in time, we observed, act on the size, and a painting executed on such a 

 ground would consequently change. We came to the couclusion, that it 

 would be necessary first to saturate the stone as deeply as possible with an 

 unctuous substance, liquified by heat, and which, solidifying as it cooled, 

 would stop up the pores of the stone. We were strengthened in this view 

 by the authority of the ancients, who sometimes passed melted wax over the 

 surface of the walls which they intended to paint, and we were induced to 

 try a coating of wax and linseed oil, rendered drying by litharge. " After 

 some experiments on stones similar to those of the cupola, we were led to 

 prefer a composition, consisting of one part wax and three parts oil boiled 

 with one tenth of its weight of litharge. The absorption took place readily 

 by means of heat, and the liquid penetrated the stone to the depth of from 

 a quarter to half an inch. The composition as it cooled acquired solidity, 

 and in six weeks or two months became hard. Having made these experi- 

 ments, we proposed to adopt the same means on the cupola, and the opera- 

 tion was to be conducted as follows. The surface was first to be scraped, 

 so as to entirely remove the paint and size, and lay the wall bare, then by 

 means of a portable furnace, the whole superficies was to be heated, about a 

 square yard at a time, and the composition was to be applied at a tempera- 

 ture of 100°, with large brushes. The first application being absorbed, a 

 second was to be added, and so on till the stone should cease to absorb. 

 To promote the absorption the stone was to be warmed repeatedly ac- 

 cording to its porousness. In every case the heat ought to be as great as 

 possible, but not so as to carbonize the oil. At length the stone being 

 saturated to a certain depth with the composition, and the surface being 

 smooth and dry, it was to receive a coat of white lead mixed with oil; and 

 on this preparation the painting was to be executed. Our plan was adopted 

 and put in execution, and thus M. Gros was enabled to produce a new 

 niasterwork which could undergo no change, except that which light and air 

 might occasion. Drops of water like dew, which covered the whole surface 

 of the cupola, every morning at first alarmed the artist; the drops appeared 

 and disappeared without the slightest had consequence, and a trial of lf> 

 years has now dissipated all apprehension." A letter is then inserted from 

 Baron Gros, certifying that in the course of 15 years his work had under- 

 gone no change. The memoir goes on to state that four pendentives in the 

 same church, painted by Gerard, were prepared in a similar manner. In this 

 case the stone was so hard that the composition could not be made to pene- 

 trate more than one eighth of an inch. The result was however quite satis- 

 factory. The painting by Gros was first begun, as before stated, in 1813, 

 and has been n centlj examined with a view to its state of preservation ; it 

 baa been pronoun ed to be in a sound and apparently unchanged condition. 

 For ordinary purposes resin might be substituted for wax, the ingredients 

 then are one part of lithargi/.ed oil to two or three parts of resin. (Ap- 

 pendix to the second Ueport of the Commissioners of the Fine Arts.) 



WIRE ROPES. ' 



Seam Wire Rape Works, 



Gateshead, ->st/, Sept., 1813. 



Sin — In your magazine for July in giving an account of the launch of the 

 " Great Britain " at Bristol, it is stated that she is to be rigged with wire 

 ropes made by a Mr. Andrew Smith; we beg to inform you that the wire 

 rigging used on board of her was manufactured by us some time previous to 

 her launch, and beg to annex a ropy of a note from T. K. Gappy, Esq., the 

 builder of the " Great Britain," which we will feel obliged by your inserting 

 along with this in your next number. 



We are, Sir, 



Your obedient servants. 



K. S. Nkw.u.i. A Co. 



Great Western Steam Ship Works, 

 Bristol, 5th Sept r, „/,<>, ■, 1843. 

 Gentlemen — In reply to your favour of the 2nd inst. I beg to inform you 

 tliat the whole of the iron wire rope used on board the Great Britain is of 

 your manufacture, and that I decided on adopting it after testing its strength 

 against other specimens. 



I am, Gentlemen, 

 Messrs. R. S. Newall & Co. Your obedient servant 



Gateshead. Thos. R. Cuppt. 



