92 TIMEHRI. 
observation. When water is warmed in a vessel ‘ts 
vapour condenses on the surfaces of surrounding ob- 
je&ts and above all on the cover of the vessel, as every- 
one can observe on the lids of soup pots, kettles, tea 
and coffee pots. ARISTOTLE reco-ds the faét in his 
“ Meteorologica.’”’ Vapour he says, condenses in the form 
of water if one takes the trouble to colleét it. He re- 
calls in another passage a less trivial faét which is 
doubtless due to chance, but which has received in the 
present day most extended application. “ Experience, 
“he adds, has taught us that sea water reduced to 
‘“‘ vapour becomes drinkable, and the vapourised produét 
‘once condensed does not reproduce salt water. Wine 
“ and all liquids, once vapourized become water.” It 
appeared therefore, according to ARISTOTLE, that evapo- 
ration changed the nature of vaporized liquids, and 
reduced them all to one identical condition—that of 
water. This change agreed with the philosophical ideas 
of the author, wine as well as sea water being thus 
reduced to the same state, that of water, the type of 
liquidity and regarded by the ancient philosophers as 
one of the four fundamental! elements of all things. 
ARISTOTLE’S remarks on sea water did not take long 
to become the origin of a praétical process, noted by 
ALEXANDER D’APHRODISIUS, one of his earliest commen- 
tators, about the 2nd or 3rd century of our era, 
Accordirg to this author sea water was warmed in pots 
of brass, and the water condensed on the surface of the 
lids colleéted for drinking. Such is the first germ of the 
distillation of sea water practised at the present day on 
so large a scale on hoard-ship. The process now 
adopted, thanks to the science of the 19th century, has 
