IXTHODL'CnuN. 21 



the human race may there present. The reader might sup- 

 pose he Avcrc perusing Kepler's Sonuiiwni A^tronomicum^ or 

 Kircher's Iter Extatiais. As Huygens, like the astronomers 

 of our own day, denied the presence of air and water in the 

 moon,* he is much more embarrassed regarding the exist- 

 ence of inhabitants in the moon than of those in tlic remoter 

 planets, whicli he assumes to be " surrounded with vapora 

 and clouds." 



The immortal author of the Philoso])hicc Natiiralis Prin- 

 cijna Matliernatica (Newton) succeeded in embracing the 

 whole uranological portion of the Cosmos in the causal con- 

 nection of its plienomena, by the assumption of one all-con- 

 trolling fundamental moving force. He first applied phys- 

 ical astronomy to solve a great problem in mechanics, and 

 elevated it to the rank of a mathematical science. The 

 quantity of matter in every celestial body gives the amount 

 of its attracting force ; a force which acts in an inverse ra- 

 tio to the square of the distance, and determines the amount 

 of the disturbances, which not only the planets, but all the 

 bodies in. celestial space, exercise on each other. But the 

 Newtonian theory of gravitation, so worthy of our admira- 

 tion from its simplicity and generality, is not limited in its 

 cosmical application to the uranological sphere, but com- 

 prises also telluric phenomena, in directions not yet fully 

 investigated ; it affords the clew to the periodic movements 

 in the ocean and the atmosphere,! and solves the problems 

 of capillarity, of endosmosis, and of many chemical, elec- 



* " Lunatn aquis carere et aere : Maiium similitudinem in Luua iiul- 

 1am reperio. Nam regioiies jilanns qww uiiuitnsis niixlto ol^scuriores 

 sunt, qiiasque vulgo pro maribus haberi video et oceanorum nomiuibua 

 insigniri, in his ipsis, longiore telescopio iiispectis, cavitates exigiias iii- 

 esse comperio rotundas, unibris intiis cadeiitibiis; quod maris supeifi- 

 ciei convenire iiequit; turn i^isi campi illi latiores non prorsus tpquabi- 

 leiii superficiem praiferunt, cum diligeutius eas intuemur. Qu(m1 circa 

 maria esse non possunt, sed materia constare debenl minus caiidicaiilo, 

 quam quae est partibus asperioribus in cpiibus rursus qua)dani viridiori 

 lumine cteteras prsecellunt." — Hngenii Cosmotkeoros, ed. alt. 169!), lib. 

 xi., p. 114. Huygens conjectures, however, that .Jupiter is agitated by 

 much wind and rain, for " ventorum flatus ex ilia nubium .fovialinm 

 mutabili facie cognoscitur" (lib. i., p. (59). These dreams of Huygens 

 logarding the inhabitants ofremotf? planets, so unworthy of a man veised 

 in exact mathematics, have, uuiortunately, been revived by Emanuel 

 Kant, in his admirable work JUgemeine Nnlurgeschichte uvd Theorie 

 des Himmels, 17.>5 (s. 173-192). 



t See Laplace {deft OHciUaf.inns de V Atmotph^re, du Jinx So/aire el 

 Lvnaire) in the M4cai?i(]iie Celnst", livre iv., and iu tlx^ Expoiition d» 

 Si/sL du Monde. 1824. p. 29l-29n. 



