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simally small quantities in some mineral waters of Ger- 

 many. Bunsen discovered these two new alkaline metals 

 in the mineral waters of Diirkheim in the Palatinate : 

 in examining the spectra of the alkalies contained in 

 these waters, he observed some bright lines which he 

 had never seen in any other alkalies which he had in- 

 vestigated. He was sure that no other metals but those 

 of the alkalies could be present, because by well known 

 chemical processes he had separated every other kind 

 of metal. Hence he concluded that these new lines 

 indicated the presence of an alkaline metal whose existence 

 has as yet been overlooked. 



So certain was Bunsen of his method, and so confident 

 was he that his bright lines could not fail him, that although 

 the weight of the substance from which he obtained his 

 result only amounted to the one thousandth part of a grain, 

 he hesitated not a moment but began to evaporate 40 tons 

 of the water, in order to get enough material to separate 

 out his new metal and examine all its chemical relations. - 



No sooner had he obtained more than a mere trace of the 

 new substance, than he found that with it was associated a 

 second new metal. He got from the 40 tons in question 

 only about 105 grains of the chloride of one metal, and 135 

 grains of the chloride of the other, in such minute quanti- 

 ties do these substances occur. Still owing to the skill and 

 industry of Bunsen, the great chemist of Heidelberg, we 

 now possess a chemical history of these two new alkalies 

 as complete and well authenticated as that of the commoner 

 alkalies. Their names, which Bunsen has wisely chosen, 

 indicate the nature of their origin and point out the pro- 

 perty by means of which they were discovered. Ccesium, 

 Bluish Grey, thus called because its spectrum is distin- 

 guished by two splendid violet hues. Rubidium owing to 

 the presence of two bright red rays at the least refrangible 

 extremity of its spectrum. Since the publication of the 

 discovery of these metals, their salts have been found to be 



