SPECULATIONS ON PHYSICAL SCIENCE 83 
came the precursors of the Axnuaires 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 
ties: 
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 
fHydrogéologte (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 
vital 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, Igoo. 
