ADDRESS. IxV 



Professor Bunscn, of Heidelberg, led the way, in 1860, in the application 

 of this new test to the hot waters of Baden-Baden and of Diirkheini in 

 the Palatinate. He observed in the spectrum some coloured lines of which 

 he could not interpret the meaning, and was determined not to rest till ho 

 had found out what they meant. This was no easy task, for it was neces- 

 sary to evaporate fifty tons of water to obtain 200 grains of what proved to 

 be two new metals. Taken together, their proportion to the water was only 

 as one to three million. He named the first cfesium, from the blnish-grey lines 

 which it presented in the spectrum ; and the second rubidium, from its two 

 red lines. Since these successful exi)erimcnts were made, thallium, so called 

 from its green line, was discovered in 1861 by Mr. Crookes ; and a foiu-th 

 metal named indium, from its indigo-coloured band, was detected by Pro- 

 fessor Eichter, of Freiberg, in Saxony in a zinc ore of the Hartz. It is 

 impossible not to suspect that the wonderful efficacy of some mineral springs, 

 both cold and thermal, in ciuing diseases, which no artificially prepared 

 waters have as yet been able to rival, may bo connected vdth the presence 

 of one or more of these elementary bodies previously unknown ; and some of 

 the newly found ingredients, when procured in larger quantities, may furnish 

 medical science with means of combating diseases which have hitherto baffled 

 aU himian skill. 



"While I was pursuing my inquiries respecting the Bath waters, I learned 

 casually that a hot spring had been discovered at a great depth in a copper- 

 mine near Ecdruth in Cornwall, having about as high a temperature as that of 

 the Bath waters, and of which, strange to say, no account has yet been 

 published. It seems that, in the year 1839, a level was driven from an old 

 shaft so as to intersect a rich copper-mine at the depth of 1350 feet from 

 the surface. This lode or metalhferous fissure occurred in what were for- 

 merly called the United Mines, and which have since been named the Clif- 

 ford Amalgamated Mines. Through the contents of the lode a powerful 

 spring of hot water was observed to rise, which has continued to flow with 

 undiminished strength ever since. At my request, Mr. Horton Davey, of 

 Redruth, had the kindness to send up to London many gallons of this water, 

 which have been analyzed by Professor WiUiam Allen Miller, F.R.S., who 

 finds that the quantity of solid matter is so great as to exceed by more than 

 four times the proportion of that yielded by the Bath waters. Its compo- 

 sition is also in many respects very different ; for it contains but little sul- 

 phate of lime, and is almost free from tlie salts of magnesium. It is rich in 

 the chlorides of calcium and sodiiim, and it contains one of the new metals- 

 caesium, never before detected in any mineral spring in England: but its 

 peculiar characteristic is the extraordinary abundance of lithium, of which a 

 mere trace had been found by Professor Roscoe in the Bath waters ; whereas 

 in this Cornish hot spring this metal constitutes no less than a twenty-sixth 

 part of the whole of the solid contents, which, as before stated, are so volu- 

 minous. "When Professor Miller exposed some of these contents to the test of 

 spectrum analysis, he gave mc an opportunity of seeing the beautiful bright 

 crimson line which the lithium produces in the spectrum. 



Lithium was first made known in 1817 by Arfvedsen, who extracted it 

 from petalite ; and it was believed to be extremely rare, until Bunsen and 

 Kii-chhoff, in 1860, by means of spectnim analysis, showed that it was a most 

 widely diffused substance, existing in minute quantities in almost all mineral 

 waters and in the sea, as well as in milk, human blood, and the ashes of some 

 plants. It has already been used in medicine, and we may therefore hope 

 that, now that it is obtainable in large quantities, and at a much cheaper rate 



1864. e 



