•58 THE CANADIAN NATURALIST. [Vol. vii. 



and explicable according to Sonstadt only " by supposing the 

 gold to be present in the sea-water as an aurate, so as to be 

 thrown down as aurate of barium. This view has much in its 

 favour, and is greatly supported by the fact that if oxalic acid is 

 added to sea-water some time before the addition of chloride of 

 barium it is scarcely possible to detect gold in the precipitate 

 formed. And this is easily to be understood, since oxalic acid 

 reduces all gold salts." 



Sonstadt even goes so far as saying that it is conceivable that 

 the method of precipitation with barium chloride might be em- 

 ployed upon the large scale, by receiving the water at high-tide 

 in large tanks and adding solution of barium chloride, the pre- 

 cipitate being removed from time to time, during low-tide. 



The third method described by Sonstadt consists in the addi- 

 tion of a few grammes of ferrous sulphate to a litre of sea -water, 

 this being followed in a few days by the addition of solutions of 

 stannous and mercuric chlorides. Mercury is thus precipitated, 

 and as it subsides carries down the gold and silver in the form of 

 an amalgam. " This method is open to objection, as being more 

 troublesome than the preceding methods." For further details 

 the reader is referred to the orio-inal article in the Chemical 

 Mews. 



OBITUARY. 



ADAM SEDGWICK. 



Geology has lost her veteran leader ! While yet firm in intel- 

 lect, full of kind and generous feeling, and occupied on the last 

 pages of the latest record of his labours, in the ninth decade of a 

 noble life, Sedgwick has gone to his rest. Under the shadow of 

 this great loss we look back through more than half a century, 

 and behold no more conspicuous figure in the front ranks of 

 advancing geology than the strenuous master workman, the 

 eloquent teacher, the chivalrous advocate of science, who has now 

 finished his task. Severe illness, borne with fortitude, had gra- 

 dually withdrawn him from scenes once brightened by his ever- 

 welcome presence, but could not tame the high spirit, or cloud 

 the genial sympathies which had won for him, more than for 

 other men, the loving admiration of his fellows in age and fol- 

 lowers in study. Rarely has a patriarchal life been crowned 

 with such enduring and affectionate respect. 



