3QO SCIENTIFIC RECREATIONS. 



ALLOYS are combinations of metals which are used for many purposes, 

 and become harder in union. Amalgams are alloys in which mercury is one 

 constituent. Some of the most useful alloys are under-stated : 



Name of Alloy. Composition. 



Aluminium bronze . . . Copper and aluminium. 



Bell metal .... Copper and tin. 



Bronze 



Gun metal . ., 



Brass .'' . . . . Copper and zinc. 



Dutch metal .... 



Mosaic gold .... ,, 



Ormulu 



Tombac 



German silver .... Copper, nickel, and zinc. 



Britannia metal ... Antimony and tin. 



Solder ..'... 



Pewter Tin and lead. 



Type metal .... Lead and antimony (also copper at times). 



Shot . . :.-i : . . . Lead and arsenic. 



Gold currency > .; ,. Gold and copper. 



Silver currency . " :. . , ' . Silver and copper. 



Stereotype metal . . . Lead, antimony, and bismuth. 

 Metals combine with chlorine, and produce chlorides, 

 Metals sulphur sulphides, 



Metals oxygen oxides, and so on. 



The metals may be classed as follows in divisions : 



Metals of the alkalies . . as POTASSIUM, SODIUM, LITHIUM, AMMONIUM. 



Metals of the alkaline earths as BARIUM, CALCIUM, MAGNESIUM, STRONTIUM. 



Metals of the earths. . . as i ALUMINIUM, Cerium, Didymium Erbium Glucinium, 



I Lanthanum, Terbium, Thorium, Yttrium, Zirconium. 

 Metals proper 



Common Metals as I IRON ' MANGANESE > COBALT, NICKEL, COPPER, Bismuth,, 



S i LEAD, TIN, ZINC, CHROMIUM, Antimony. 



Noble Metals . as * MERCURY SILVER, GOLD, PLATINUM, Palladium, Rho- 



1 dium, Ruthenium, Osmium, Iridium. 



We cannot attempt an elaborate description of all the metals, but we 

 will endeavour to give a few particulars concerning the important ones,, 

 leaving many parts for Mineralogy to supplement and enlarge upon. We 

 shall therefore mention only the most useful of the metals in this place, 

 We will commence with POTASSIUM. 



METALS OF THE ALKALIES. 



POTASSIUM has a bright, almost silvery, appearance, and is so greatly 

 attracted by oxygen that it cannot be kept anywhere if that element be present 

 not even in water, for combustion will immediately ensue on water ; and 

 in air it is rapidly tarnished. It burns with a beautiful violet colour, and 



