Of other metals first detected by the spectroscope mention is to be made of indium, determiped by F.
Rubidium, caesium, thallium, indium and gallium were first discovered by means of this instrument; the study of the rare earths is greatly facilitated, and the composition of the heavenly bodies alone determinable by it.
To take an example: 38 parts of indium combine with 35.4 parts of chlorine; hence, if the formula of the chloride be InCI, InC1 2 or InC1 3, indium has the atomic weights 38, 76 or 114.
The specific heat of indium is o 057; and the atomic heats corresponding to the atomic weights 38, 76 and 114 are 3.2, 4.3, 6.5.
We must refer to Kayser and Runge's Handbuch for further details, as well as for information on other spectra such as those of silver, thallium, indium and manganese, in which series lines have been found.
The elements gallium and indium were discovered in blende.