152 G. H. KNIBBS. 



(6) Wright, 1750.— In 1750 Thomas Wright of Durham published 

 "An original theory or new hypothesis of the universe, etc." 1 in 

 which the sixth 'letter' bears the title "of general motion amongst 

 the stars, etc." He requires it to be granted that "all the stars 

 are, or may be, in motion." These speculations of Wright's, on 

 the nature of the stellar universe, were known to Kant prior to 

 the production of his work on the same subject. 2 



(7) Kant, 1755. — It was however not till a period of about five 

 years after the appearance of Wright's theories, that Kant published 

 anonymously, his remarkable "Allgemeine Naturgeschichte und 

 Theorie des Himmels," 3 in which he sketched his view of the 

 development and mechanics of the entire sidereal system, one 

 feature of which was the " nebular hypothesis " of the genesis of 

 planetary systems. It was through these offices that the human 

 mind was familiarized with the larger conception of general stellar 

 movement. 



(8) Mayer, 1760. — Five years later again, that is after the 

 appearance of Kant's work, Tobias Mayer, in 1760, in a memoir 

 presented to a Gottingen Society, 4 compared the places of 80 

 stars observed by Roemer in 1706 with his own observations 

 in 1756 and Lacaille's in 1750. Out of these, from 15 to 20 

 shewed differences in declination or right ascension exceeding 15"; 

 and in the cases of Arcturus, Sirius, Procyon, Altair, Piscis Aus- 

 trinus, the differences were so great that there could be no question 

 as to the reality of the stellar motion. Mayer pointed out that 

 the sun, as well as the stars, might be conceived as having 

 absolute motion. 



(9) Lambert, 1761. — In 1761 Heinrich Lambert 5 published some 

 speculations concerning the universe, surmising that "everything 

 revolves" the earth round the sun, the sun round the centre of his 



1 Lond. 4to. pp. xii.+84, plates 32. See also Phil. Mag., April 1848, 

 pp. 241 - 252. — De Morgan's account of Wright's speculations. 



2 Kant, according to Struve, obtained his knowledge of Wright's view 

 from the Hamburgische freie Urtheile of 1751. 



3 Leipzic, 8vo 1755. 4 Opera Inedita, 1775. 

 5 Cosmologische Briefe, Augsburg 1761. 



