PHOSPHORIC ACID 



555 



Experiments on the capacity of phosphor-bronze to resist the oxidation of sea-water : 

 Best English copper-sheets lost during six months immersion in sea-water 3'058 

 per cent. Phosphor-bronze sheets lost only 1-158 per cent. 



To these may be subjoined the following results obtained by Messrs. Montefiore : 



Belgian Experiment. Ordinary bronze always contains a larger or smaller amount 

 of oxide in suspension. This has been contested by various authorities, as it was not 

 possible to prove the presence of oxide of tin in the bronze by analysis, the oxido 

 not being reduced by hydrogen at the temperatures which can be produced in labora- 

 tories. 



By a longer series of experiments Messrs. Montefiore and Kiint/el have now defi- 

 nitely proved the presence of oxide of tin and sub-oxide of copper. The presence of 

 oxido greatly lessens the tenacity, elasticity, and tensile strength of the bronze. 

 Various experiments were made in this direction. They melted shavings of old 

 bronze and cast a bar thereof at 1,525 Cent. The remaining liquid bronze was 

 stirred with a wooden stick (poled) and a second bar cast at 1,668 Cent. The re- 

 maining metal was deoxidised with phosphorus and a bar then cast at 1,614. Then 

 three castings were thus made out of the same crucible and in the same manner into 

 three iron moulds. The results were as follow : 



Thus by the entire reduction the old bronze has tripled its tenacity and considerably 

 augmented its absolute resistance. 



Messrs. Alex. Dick and Co. have very recently established at Blackfriars Eoad 

 London, a special foundry for phosphor-bronze casting, and have also made arrange- 

 ments in Birmingham for the production of sheets, wire, &c. 



The Table on p. 556 shows the results of Experiments to ascertain the Tensile 

 Strength and the Resistance to Torsion of various Wires received from A. Dick, Esq., 

 and made by Mr. David Kircaldy, of the testing and experimental works in Southwark. 



PHOSPHORIC ACID exists abundantly in the mineral kingdom : it is found in 

 several of the igneous rocks, in combination chiefly with lime. In the vegetable king- 

 dom, it is discovered in the ashes of many plants, and it forms a large and important 

 portion of the animal kingdom. Anhydrous phosphoric acid, is the acid formed by the 

 vivid combustion of phosphorus. Monobasic or mctaphospkorio acid, commonly 

 known as glacial phosphoric acid, is now much employed in England, though for somo 

 time it did not attract the attention which it deserves in the arts and manufactures of 

 this country. For many of the wants of the dyer, the calico-printer, the enameller, 

 and even in the purification of some oils and fat, the glacial phosphoric acid has much 

 to recommend it over any of the common acids at present in use. Nor need its price 

 prove an obstacle to its introduction as a practical agent. Finely ground bone-ash, 

 digested with a due proportion of oxalic acid and water, readily yields a solution of 

 phosphoric acid, which requires only to be evaporated in a proper vessel to furnish at 

 once this useful article. (Urc.) Unlike sulphuric and other strong acids, it is not 

 decomposed by organic matter ; and might hence be employed with great advantage 

 in the precipitation of carmine and other delicate vegetable colours, as well as for 



