(_a_) BRITISH EMPIRE: 16 _Europe_: United Kingdom. _Asia_: India (Burma). _Africa_: Rhodesia; Union of South Africa. _America_: Canada; Newfoundland. _Australasia_: Australia; New Zealand. CHAPTER III =SOURCES OF SUPPLY OF PLATINUM METALS= (_b_) FOREIGN COUNTRIES: 32 _Europe_: France; Finland; Germany; Lapland; Russia; Spain. _Asia_: Armenia; Borneo; China; Japan; Sumatra. _Africa_: Congo Free State; Madagascar. _America_: Brazil; Colombia; Ecuador; Mexico; United States. WORLD MAP OF PLATINUM DEPOSITS 59 REFERENCES TO LITERATURE ON THE PLATINUM GROUP 60 NOTE.—_Numerals in square brackets in the text refer to the Bibliography at the end._ THE PLATINUM METALS CHAPTER I PLATINUM METALS: THEIR OCCURRENCES, CHARACTERS AND USES INTRODUCTION The metals which comprise the Platinum group are the following: Platinum, Palladium, Iridium, Osmium, Ruthenium and Rhodium. Up to the year 1914 Russia produced over 90 per cent. of the world’s supply of platinum, the Republic of Colombia, South America, ranking next in importance with about 5 per cent. Owing, however, to the war and to the chaotic conditions brought about by the revolution, the output of Russia has considerably decreased, and although the Colombian production has been steadily increasing, the increased demand in connection with munition manufacture caused a somewhat serious shortage during the latter stages of the war, which was especially felt in the United States. As a result much exploratory work has recently been carried on in an endeavour to discover new deposits of importance; but up to the present, although several fresh occurrences have been brought to light, results have on the whole been disappointing. OCCURRENCES Platinum usually occurs in nature as native metal alloyed with one or more of its allied metals in the form of very fine grains more or less flattened; sometimes in the form of irregular nuggets; and occasionally, though rarely, in small cubic crystals. It is sometimes coated with a black layer of iron oxide, which may be magnetic, in which case it is not easily recognizable. When unrefined it is referred to as “crude” platinum.