SPECULATIONS ON PHYSICAL SCIENCE 83 



came the precursors of the Annuaires du Bureau des 

 Longitudes. 



An observation of Lamarck's on a rare and curious 

 form of cloud has quite recently been referred to by 

 a French meteorologist. It is probable, says M. E. 

 Durand-Greville in La Nature, November 24, 1900, 

 that Lamarck was the first to observe the so-called 

 pocky or festoon cloud, or mammato-cirrus cloud, 

 which at rare intervals has been observed since his 

 time.* 



Full of over confidence in the correctness of his 

 views formed without reference to experiments, 

 although Lavoisier, by his discovery of oxygen in 

 the years 1772-85, and other researches, had laid 

 the foundations of the antiphlogistic or modern 

 chemistry, Lamarck quixotically attempted to sub- 

 stitute his own speculative views for those of the 

 discoverers of oxygen — Priestley (1774) and the 

 great French chemist Lavoisier. Lamarck, in his 

 Hydrogdologie (1802), went so far as to declare : 



" It is not true, and it seems to me even absurd to 

 believe that pure air, which has been justly called 

 vita/ air, and which chemists now call oxygen gas, can 

 be the radical of saline matters — namely, can be the 

 principle of acidity, of causticity, or any salinity 

 whatever. There are a thousand ways of refuting 

 this error without the possibility of a reply. . . . 

 This hypothesis, the best of all those which had been 

 imagined when Lavoisier conceived it, cannot now 

 be longer held, since I have discovered what is really 

 caloric" (p. 161). 



* Nature, Dec. 6, 1900. 



