xviii THE ELEMENTS AND LIFE 359 



essential constituents of protoplasm ; the second showing 

 the ten which are the most important constituents of the 

 earth's mass as known to geologists and physicists. The 

 four which are italicised in the first list do not appear in the 

 second, and cannot, therefore, be considered as forming an 

 essential portion of the rock-structure of the earth, although 

 without them it seems fairly certain that the life-world could 

 not have existed. 



The Elements in Relation to Man 



So far as we can see, therefore, the fourteen elements in 

 these two lists would have sufficed to bring about all the 

 essential features of our earth as we now find it. All the 

 others (more than sixty) seem to be surplusage, many 

 exceedingly rare, and none forming more than a minute 

 fraction of the mass of the earth or its atmosphere. All except 

 seven of these are metals, including (with iron) the seven 

 metals known to the ancients and even to some prehistoric 

 races. The seven ancient metals are gold, silver, copper, 

 iron, tin, lead, and mercury. All of these are widely 

 distributed in the rocks. They are most of them found 

 occasionally in a pure state, and are also obtained from their 

 ores without much difficulty, which has led to their being 

 utilised from very early times. But though these metals 

 (except iron) appear to serve no important purpose either in 

 the earth itself or in the vegetable or animal kingdoms, they 

 have yet been of very great importance in the history of 

 man and the development of civilisation. From very remote 

 times gold and silver have been prized for their extreme 

 beauty and comparative rarity ; the search after them has 

 led to the intercourse between various races and peoples, and 

 to the establishment of a world-wide commerce ; while the 

 facility with which they could be worked and polished called 

 forth the highest powers of the artist and craftsman in the 

 making of ornaments, coins, drinking-vessels, etc., many of 

 which have come down to us from early times, sometimes 

 showing a beauty of design which has never been surpassed. 

 Our own earliest rudiments of civilisation were probably 

 acquired from the Phoenicians, who regularly came to 

 Cornwall and our southern coasts to purchase tin. 



