The _Metallarbeiter_ remarks that metals have in most cases experienced a reduction in value of late years, this depreciation being attributed in some measure to the cheaper methods of obtaining metals as well as to the discovery of new sources of mineral wealth. The following comparative table shows the approximate prices of various metals in December, 1874, and December, 1884: Dec., 1874. Dec., 1884. Per lb. Per lb. £ s d. £ s. d. Osmium 71 10 0 62 0 0 Iridium 70 0 0 45 0 0 Gold 62 15 0 63 0 0 Platinum 25 7 6 21 7 6 Thallium 23 17 6 4 15 0 Magnesium 10 5 0 1 15 0 Potassium 5 0 0 4 0 0 Silver 3 17 6 (in Hamburg) 3 7 6 Aluminum 1 16 0 1 16 0 Cobalt 1 14 0 1 2 0 Sodium 0 14 2 0 8 8 Nickel 0 11 0 0 3 1 Bismuth 0 8 1 0 8 1 Cadmium 0 7 1 0 4 0 Quicksilver 0 2 0 (in London) 0 1 9 Tin 0 1 1 (in Berlin) 0 0 9 Copper 0 0 10 (" " ) 0 0 7 Arsenic 0 0 8 0 0 4-1/2 Antimony 0 0 6-1/4 (" " ) 0 0 5 Lead 0 0 2-3/4 (" " ) 0 0 1-3/8 Zinc 0 0 2-1/2 (" " ) 0 0 1-3/4 Steel 0 0 1-3/8 ( in 0 0 0-3/4 Bar iron 0 0 1-1/8 Upper 0 0 0-5/8 Pig iron 0 0 0-7/16 Silesia ) 0 0 0-1/4 Gold now ranks highest in value of all metals, the competition of osmium and iridium having been over come. It is only by reason of improved methods of preparation that the latter have become cheaper, while their use has at the same time increased. Iridium is mixed with platinum in order to increase its strength and durability. The normal standards of the metrical system are made of platinum-iridium on account of its known immutabilty. In 1882, platinum stood 15 per cent. below its present value; but its increased employment for industrial purposes led to the subsequent improvement in price. Thallium has experienced a severe depreciation on account of the economical process by which it is extracted from the residue of the lead chambers used in the manufacture of sulphuric acid. The use of this metal is mainly confined to experimental purposes. The fall in silver has arisen from increased production and diminished use for coinage.