226 ANNUAL OF SCIENTIFIC DISCOVERT. 



submitting a globule suddenly to a very high temperature, it 

 burns with explosion, sending out bluish sparks. Cerium powder 

 can inflame below 100°. 



THE NEW METALS. 



The "Boston Journal of Chemistry " says : We presume but 

 comparatively few of our readers have had ©iDportunities of ex- 

 amining the new metals brought to light by spectrum analysis. 

 The two most remarlvable, ceesium and rubidium, are strikingly 

 like the metal potassium ; and so greedy are they for oxygen, it 

 is necessary to keep them constantly immersed in pure naphtha. 

 The expense of eliminating these rare and sparsely disseminated 

 metals is so great that their cost is marvellously high. A speci- 

 men of rul)idium in our possession cost us at tlie rate of more than 

 7,000 dollars a pound, or 1 dollar the grain. These two new alka- 

 line metals were discovered by Bunsen, a few years ago, wliile ex- 

 perimenting upon some mineral waters with tlie spectroscope. By 

 no other method of analysis could they have been discovered. In 

 examining the w^aters, he observed some bright lines he had not seen 

 in any other alkalies which he had investigated. He felt certain 

 that these lines indicated a new metal or metals, just as Adams 

 and Leverrier, from the perturbations of the planet Uranus, were 

 convinced of the existence of Neptune. The amount present in 

 the substance examined could not exceed the one-thousandth part 

 of a grain ; hence, the quantity held in the water was infinitesi- 

 mal. To obtain a manageable quantity, Bunsen evaporated 40 

 tons of the Darkheim Spring water, and from this vast amount 

 obtained of caesium only 105 grains of the chloride, and of rubid- 

 ium 135 grains ! How fevv know anything of the magnitude of 

 the labors of chemists engaged in research ! Since the discovery 

 of the new metals in the spring-water of Durkheim, they have 

 been found in many other springs, in mica and other old Plutonic 

 silicates; also, in the ashes of beet-root, tobacco, coffee, and 

 grapes. The mineral lepidolite contains considerable rubidium, 

 and most of the specimens in the hands of chemists were obtained 

 from that mineral. We cannot predict for the new alkaline met- 

 als any very great practical use in the arts. 



The other new and interesting metals which we find in our col- 

 lection are lithium, thallium, and indium. The first of these is of 

 white color, and fuses at 180°. It is the lightest metal known, 

 being almost as light as cork. Before spectrum analysis was dis- 

 covered it was supposed the lithium salts were very rare ; but the 

 wonderful spectroscope reveals their jDresence in almost all waters, 

 in milk, tobacco, and even in human blood. A very strange plant 

 is the tobacco-plant. How singular, that atoms of the rarest and 

 most remarkable of all the metals — ciesium, rubidium, and lith- 

 ium — should be found in this pungent w- eed ! When volatile 

 lithium compounds are heated in fiame, they impart to it a most 

 magnificent crimson tinge; nothing in ordinary pyri)techny can 

 compare with it. If one six-thousandth part of a grain of lithium 



