ALUMINIUM-BRONZE 131 



Unless some cheaper method of eliminating tho metal than by the agency of sodium 

 be discovered. 



Mr. Gordon has shown that the amount of tension which aluminium wire was 

 capable of resisting will be found to bo between that of the best iron and tho best 

 steel wire. 



Probably one of the most interesting of the applications of aluminium (at least in 

 a scientific point of view) that has been made, is that by Deville and Wohler, of 

 employing it in the production of crystalline allotropic modifications of certain other 

 elements previously unknown in that state e.g. boron, silicon, and titanium. It 

 depends upon the fact that these elements, in tho amorphous state, dissolve in fused 

 aluminium, and on cooling the molten solution, they slowly separate from the 

 aluminium in the crystalline state. 



Aluminium may be gilded by being dipped into a solution of the hyposulphite of 

 gold after it has been well cleaned by the successive use of potash, nitric acid, and 

 water. Aluminium is soldered with difficulty. The most successful method is to coat 

 the aluminium with copper by the electrotype process, after which- soldering can be 

 effected in the usual way. 



AIiTnwciNIITlW-BROTJrZE. This alloy was a discovery of Dr. John Percy, 

 F.E.S., and it appears to be a true chemical compound. Mr. I. L. Bell, who manu- 

 factured this beautiful metallic compound on a large scale, thus describes its manufac- 

 ture : ' Copper is melted in a plumbago crucible, and, after being removed from 

 the furnace, the solid aluminium is added. The union of the two metals is attended 

 with such an increase of temperature, that the whole becomes white hot,. and unless 

 the crucible containing the mixture is of a refractory material, it is fused by the 

 intensity of the heat. A vessel which has resisted a heat sufficient to effect the fusion 

 of copper has been melted when tho aluminium has been added.' 



The value of aluminium-bronze will be gathered from the following statement of 

 results obtained by Lieut.-Colonel A. Strange, F.K.A.S., and communicated by him 

 to the Astronomical Society. Lieut.-Colonel Strange recommended this metal as a 

 valuable material for the construction of astronomical and other philosophical 

 instruments. Eegarding the most important qualities as 1. Tensile strength; 

 2. Eesistance to compression ; 3. Malleability ; 4. Transverse strength or rigidity ; 

 5. Expansive ratio ; 6. Founding qualities ; 7. Behaviour under files, cutting tools, 

 &c.; 8. Kesistance to atmospheric influences ; 9. Fitness to receive graduation ; 

 10. Elasticity ; 11. Fitness for being made into tubes ; 12. Specific gravity experi- 

 ments were made to determine each of those conditions. 



Tensile strength. The result of trials by Mr. Anderson of Woolwich was the 

 average tenacity of this metal proved to be 22 tons 12 cwt. (50,624 Ibs.) breaking 

 weight per square inch. Elongations did not take place until 4,300 Ibs. in the 

 one case, and 3,600 Ibs. in the other had been applied, when a permanent elonga- 

 tion was noticed of '009 of an inch in the first specimen and '034 of an inch in 

 the last. 



Resistance to compression. The ultimate amount of compression applied was 

 59 tons 2 cwt. 1 qr. 4 Ibs. (132,416 Ibs.), under which the specimen became much 

 distorted. ' The specimen subjected to this enormous pressure, distorted though it 

 is, does not exhibit the trace of a fissure. The cohesion of its particles is inviolate.' 

 Compression was not perceptible until 9 tons 2 cwt. per square inch (20,384 Ibs.) 

 was applied, when the specimen gave way to the extent of '006 of an inch ; and on 

 the weight being removed an elasticity of '001 was observed, which gives the first 

 permanent compression as '005 of an inch. 



Malleability. The quality of this metal for forging purposes would appear to be 

 excellent. There were specimens in the International Exhibition of 1862, showing 

 that the alloy could be drawn out under the hammer almost to a needle-point. 



Transverse strength. These experiments were made by Messrs. Simms. Tho same 

 weight applied to these bars altered the index of the instrument as under : 



Brass 2-22 divisions 



Gun-metal O f 15 



Aluminium-bronze 0'05 



Hence aluminium-bronee is 3 times more rigid than gun-metal, and 44 times more 

 rigid than brass. 



Expansive ratio. Aluminium-bronze is affected by change of temperature a little 

 less than gun-metal, and much less than brass. 



Founding qualities. The alloy produces admirable castings of any size. 



Behaviour under files, cutting tools, $c. 'In this respect it leaves nothing to be 





