3. _Allgemeine Naturgeschichte und Theorie des Himmels_, published anonymously in 1755 (4th ed. 1808; republished H. Ebert, 1890). In this remarkable work Kant, proceeding from the Newtonian conception of the solar system, extends his consideration to the entire sidereal system, points out how the whole may be mechanically regarded, and throws out the important speculation which has since received the title of the nebular hypothesis. In some details, such e.g. as the regarding of the motion of the entire solar system as portion of the general cosmical mechanism, he had predecessors, among others Thomas Wright of Durham, but the work as a whole contains a wonderfully acute anticipation of much that was afterwards carried out by Herschel and Laplace. The hypothesis of the original nebular condition of the system, with the consequent explanation of the great phenomena of planetary formations and movements of the satellites and rings, is unquestionably to be assigned to Kant. (On this question see discussion in W. Hastie's _Kant's Cosmogony_, as above.) 4. _Meditalionum quarundam de igne succincta delineatio_ (1755): an inaugural dissertation, containing little beyond the notion that bodies operate on one another through the medium of a uniformly diffused, elastic and subtle matter (ether) which is the underlying substance of heat and light. Both heat and light are regarded as vibrations of this diffused ether. 5. _On the Causes of Earthquakes_ (1755); _Description of the Earthquake of 1755_ (1756); _Consideration of some Recently Experienced Earthquakes_ (1756). 6. _Explanatory Remarks on the Theory of the Winds_ (1756). In this brief tract, Kant, apparently in entire ignorance of the explanation given in 1735 by Hadley, points out how the varying velocity of rotation of the successive zones of the earth's surface furnishes a key to the phenomena of periodic winds. His theory is in almost entire agreement with that now received. See the parallel statements from Kant's tract and Dove's essay on the influence of the rotation of the earth on the flow of its atmosphere (1835), given in Zollner's work, _Ueber die Natur der Cometen_, pp. 477-482. 7. _On the Different Races of Men_ (1775); _Determination of the Notion of a Human Race_ (1785); _Conjectural Beginning of Human History_ (1786): three tracts containing some points of interest as regards the empirical grounds for Kant's doctrine of teleology. Reference will be made to them in the notice of the _Kritik of Judgment_.