222 History of Luminescence 



example, the quenching action of infrared rays on phosphorescence 

 and the phenomena of quenching in general, but these discoveries 

 are best left to the chapters on special types of luminescence. 



The Light of Living Things 



During the century, naturalists greatly extended the list of known 

 luminous species of animals. The luminous fire-cylinder (Pyrosoma) 

 of F. Peron (1804) , the brittle stars and sandfieas of D. Viviani 

 (1805), the radiolaria of W. G. Tilesius (1819) and the siphono- 

 phores of F. J. F. Meyen (1834) were described. Luminescence came 

 to be recognized as a phenomenon well scattered among the simpler 

 organisms of the animal kingdom. 



JAMES MACARTNEY 



Important monographs -^ also appeared; for example, the much 

 quoted " Observations on Luminous Animals " (1810) by J. Macart- 

 ney. The Macartney paper of thirty-five pages in the Phil. Trans. 

 contained his own results and also observations of Sir Joseph Banks, 

 a member of Capt. Cook's voyage in 1768-1771. Medusae, shrimp, 

 ctenophores, fireflies, Pyrophorus, and Noctiluca were figured. From 

 the facts regarding marine phosphorescence, Macartney also took 

 the definite stand that it was always due to living animals. He 

 regarded the light as appearing " only at certain periods, and in 

 particular states of the animal's body " and " is commonly produced 

 or increased by a muscular effort; and is sometimes absolutely de- 

 pendent upon the will of the animal. . . . The power of shewing 

 light resides in a peculiar substance or fluid," which is sometimes 

 situated in a particular organ, and sometimes diffused throughout 

 the animal's body. Macartney wrote: 



The luminous matter, in all situations, so far from possessing phosphoric 

 properties, is incombustible, and loses the quality of emitting light by 

 being dried, or much heated. The exhibition of light, however long 

 it may be continued, causes no diminution of the bulk of the luminous 

 matter. It does not require the presence of pure air, and is not extin- 

 guished by other gases. . . . The luminous property does not appear to 

 have any connection with the oeconomy of the animals which possess it, 



^^ In 1821 the last of the Latin theses on luminescence appeared, an octavo tract of 

 85 pages, entitled De animalibus phosphorescentibus by Johan Marcus Baart de la 

 Faille. The work is divided into three chapters, the first dealing with luminous living 

 terrestrial animals, the second with marine forms and the third with dead animals. 

 Baart de la Faille gave no original observations but compiled his facts from many 

 authors, particularly Cohausen (1717), Macartney (1810), and Treverinus (1818). 

 D. Viviani's Phosphorescentia maris (Genoa, 1805, 15 pp.) , was an earlier thesis in 

 Latin. 



