MECHANICS AND USEFUL ARTS. 81 



The bars maybe worked hot, as easily as the best quality of steel. Acad- 

 emy of Sciences of Paris. 



(The bronze here spoken of, is formed of 90 or 95 parts of copper, and 10 

 or 15 parts of aluminum.) 



SILVER IN BELLS. 



The public have heard more or less about the liberal use of silver in bell- 

 metal, and how some apocryphal bells are supposed to contain at least half 

 their weight of this precious alloy, a myth in which many people persist 

 in believing even clown to the present clay. But silver is not a sonorous 

 metal; and from experiments made with standard silver bells, it has been 

 shown, beyond dispute, that they have very little sound, and that little, too, 

 is of the harshest and most unmusical kind. With a view of definitely test- 

 ing the effect of a slight admixture of silver upon the tone of a bell, Messrs. 

 Mears made four very small ones of the same metal as the great bell for the 

 Westminster clock. In one of these, Is. Qd. worth of silver was put, in 

 another Is. worth, in the third 6d. worth, and in the fourth none. The mis- 

 chievous effects of even this slight quantity of silver were here clearly shown; 

 for that which had the least amount in it was the least injured in tone, and 

 that which had none was the best sounding bell of all. London Times. 



DESTRUCTIVE EFFECTS OF RED LEAD UPON IRON. 



Mr. Robert Lament, who was, a few months back, requested by the man- 

 agers of one of the largest steam packet companies in the kingdom to make 

 a report on the merits of certain compositions used to a large extent in Liv- 

 erpool for the preservation of iron ships, and to prevent fouling on the bot- 

 toms of such vessels, has come to the conclusion, so far as regards the use 

 of red lead, or paints containing lead, quite at variance with the popular 

 notion upon the subject, by declaring the use of that pigment for coating 

 iron vessels to be most pernicious. And in this hypothesis he is confirmed 

 by the opinion of Mr. Nathan Mercer, F. C. S., who, after inspecting the 

 iron ship William Fairburn, the plates of which were coated with red lead 

 prior to her late voyage to Calcutta, observes, that the ext-cnt to Avhich the iron 

 had been corroded could not fail to have attracted the attention of the most 

 superficial observer. On a close inspection, he found the red-lead coating 

 covered with blisters, from each of which, on being opened, a clear fluid 

 escaped, and left exposed on the surface of the iron a number of brilliantly 

 shining crystals of metallic lead. Mr. Mercer says each blister is, in fact, 

 a galvanic battery in miniature, and that, as wherever there is electrical 

 there must be also chemical action, the corrosion is easily accounted for. 

 This action, he says, will continue as long as any red lead remains, and is 

 necessarily at the expense of the iron. He also points out that the " sweat," 

 so well known to every person interested in iron ships, is not, as is generally 

 supposed, salt water, but a solution of chloride of iron manufactured in the 

 blisters. Mr. Mercer considers this sweating is due, in a great degree, to the 

 use of red-lead paint in immediate contact with iron; and he recommends, 

 therefore, that it should never be used as a coating for sea-going vessels, 

 unless special precautions are taken to prevent its coming into direct contact 

 with iron. Liverpool Albion. 



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