The Nineteenth Century 213 



both members of the American Philosophical Society. The book 

 merely told how to make phosphors and described some lumines- 

 cence experiments with phosphorus dissolved in oils (" liquid phos- 

 phorus ") . However, the two-volume Elements of Chemistry (New 

 Haven, 1830) , written by Benjamin Silliman himself, contained an 

 adequate section devoted to all kinds of luminescence under the 

 heading: " Light is Emitted as well as Absorbed by Bodies." The 

 section dealt with (a) solar phosphori (diamonds) ; (b) artificial 

 solar phosphor (Canton's preparation and the Bolognian and Bal- 

 dewinian phosphorus; (c) phosphorescence by heat (fluorspar) ; (d) 

 light by percussion, friction or pressure (quartz, borax, bonnet 

 cane) ; (e) phosphorescence is seen in some animals (glowworm, 

 firefly, sea water) ; (/) phosphorescence is produced by chemical 

 action (slaking lime, potassium and sulphur, iodine and phosphorus, 

 etc.) . Silliman was particularly interested in minerals and described 

 a number of places near New Haven where thermoluminescent or 

 triboluminescent varieties could be obtained. 



Perhaps the best known chemistry ^^ text which dealt adequately 

 with luminescence was that of Leopold Gmelin (1788-1853), pro- 

 fessor of medicine and chemistry at the University of Heidelberg 

 and an associate of Tiedemann. The Gmelin family have been 

 famous as physicians, pharmacists, and chemists since the beginning 

 of the eighteenth century. The first edition of his Handbuch der 

 theoretorische Chemie appeared in 1817-1819, and was followed by 

 three other editions, the last in 1843-1855.^^ Gmelin's works were 

 translated under the auspices of the Cavendish Society by Henry 

 Watts (eighteen volumes between 1848-1871) as a Handbook of 

 Chemistry. In volume one (1848) of Watts' translation, pages 181- 

 208 were devoted to " Development of Light by Ponderable Sub- 

 stances." They contain a surprisingly complete account of the 

 known types of luminescence, based largely on the general work of 

 Heinrich and Dessaignes, and the later book of F. Tiedemann 

 (1830). 



Luminescence of living animals and plants and putrefying ani- 

 mals and wood is classified under the head of " Development of 

 Light as a Consequence of Probable Chemical Combination " and 

 contrasted with " The Development of Light Unaccompanied by any 



^* Among other textbooks of chemistry, considerable discussion of luminescences will 

 be found in the ones written by John Murray (1819) , and J. F. Daniell (1839) , while 

 those of T. Thomson (1802) . F. Accum (1803) , A. F. Fourcroy (1804) , L. J. Thenard 

 (1816) , E. Turner (1827) , J. B. Dumas (1828-1846, 8 v.) . F. A. C. Gren and C. F. 

 Bucholz (1839) , J. W. Draper (1847) and J. Troost (1865) make no mention or 

 present only trifling facts on the subject. 



^* Later editions have appeared and even today the revised Gmelin-Kraut Handbuch 

 der Anorganische Chemie is a standard reference book on the subject. 



