406 ANNUAL RECORD OF SCIENCE AND INDUSTRY. 



were discernible. Chemical analysis of an air-dried sample 

 gave the following proportional comjDOsition: Phosphoric acid, 

 35.315; lime, 32.V64; magnesia, 1.'7 25 ; sesquioxide of iron, 

 0.590; potash, a trace; chloride of sodium, 0.820; sulphuric 

 acid, 1.290; carbonic acid, 2.31 ; silica, 0.210; insoluble mat- 

 ter, 0.540 ; organic matter, 6.9 ; water, on drying at 212, 7.3. 

 The amount of nitrogen was 0.351 per cent. The amount of 

 phosphoric acid corresponds to '77 per cent, of phosphate of 

 lime, so that it is as important an article as Baker guano for 

 the manufacture of superphosphates. 32 (7, Aj^i^il 12, 1873, 

 199. 



DISCOVERY AND USE OF NATURAL PHOSPHATES. 



According to Dr. Meyer, the discovery of phosphorus in 

 human urine, in 1669, by the alchemist Brand, did not reveal 

 its importance in the economy of nature ; and although, be- 

 fore 1700, its existence in some plants had also been demon- 

 strated, no one seemed to suspect a connection between 

 these facts, nor to inquire into the source of the phosphorus 

 in either case, nor recognize in it a universal and indisj^ensa- 

 ble constituent of the animal and vesjetable kino^doms. Phos- 

 phoric acid was, of course, discovered at the same time ; but, 

 with the transmutation theory in vogue, was regarded as a 

 mixture of oil of vitriol and muriatic acid until its specific 

 properties were pointed out by Marggrof in 1743. It is a 

 fact, indicative of the difficulties of the first stages of discov- 

 ery, that the recognition (made by Gahn) of phosphoric acid 

 in the bones did not take j^lace for a full century after the 

 detection of phosphorus, and a quarter of a century after that 

 of phosphoric acid, although bones were universally and dai- 

 ly in the hands of all classes, and seemed to be just the por- 

 tion of the body to invite the investigation of physicians, 

 who were also almost always chemists. It was, therefore, 

 a surprise when Dr. Gahn, in 1780, found the same acid abun- 

 dantly present in the mineral kingdom i pyromorphite, and 

 that Klaproth and Vauquelin ascertained that apatite was 

 similar in composition to the earthy portion of the bones. 

 The vast importance of these simple, isolated facts of the 

 discovery of phosphorus in the three natural kingdoms was 

 not dreamed of by these investigators, and they in nowise 

 suspected the part played by the acid (one similar to that 



