MISCELLANY 



637 



Kentucky State Medical Association. 

 1874. Pp. 262. 



Experiments, showing Character and 

 Position of Xeutral Axes (Nickerson, C. E.). 

 Pp. 26. 



" Do Snakes swallow their Young ? " 

 (Goode). Pp. 12. 



The Analyst, Monthly Journal of Pure 

 and Applied Mathematics. Des Moines, 

 Iowa. Pp. 20. 



Mechanical Properties of Materials of 

 Construction (Thurston). Pp. 28. 



Assaying by the Spectroscope (Du Bois). 

 Pp. 12. 



The Mystery of Life (Cox). Pp. 32. 



The Plagopterinae and the Ichthyology 

 of Utah (Cope). Pp. 14. 



Transmission of Diseases (Hamlin). 

 Pp. 9. 



Papers chiefly Anatomical (Wilder). 

 Pp. 94. 



Transformations of the House -Fly 

 (Packard). Pp. 14. 



Geographical Variation of North Ameri- 

 can Birds (Allen). Pp. 10. 



Mammals of Kansas, etc. (Allen). Pp. 23. 



Statistical Atlas of the United States. 

 Part III. Vital Statistics. 



Darwinism and Language (Whitney). 

 Pp. 30. 



MISCELLANY. 



Coggia's Comet. — The comet which lately 

 made such a grand display in our northern 

 heavens was discovered by Coggia, ;it Mar- 

 seilles, on April I'Fth. When first seen, the 

 nucleus and coma together had a diameter 

 of 100,000 miles, the comet being then 

 133,000,000 miles from the earth, and 

 153,000,000 from the sun. It travels round 

 the sun in the same direction as the planets, 

 but in an orbit the plane of which is very 

 much inclined. Of all the planetary orbits, 

 excepting those of the asteroids, that of 

 Mercury is most oblique, having a slant of 

 seven degrees ; but the inclination of the 

 orbit of Coggia's Comet is nearly ten times 

 as great, being set down at 66°. Its peri- 



helion passage, or nearest approach to the 

 sun, occurred on July 8th, when it came 

 within 62,000,000 miles of that orb, and it 

 was then moving at the rate of 160,000 

 miles an hour. It continued to approach 

 the earth until July 20th, coming, on that 

 date, within 26,000,000 miles of us, when 

 it appeared at its brightest, or, accord- 

 ing to Prof. Parkhurst, 140 times more 

 brilliant than when first discovered. Of its 

 tail, the same authority says : " On June 

 25th the observed length of the tail was 

 computed as 3,000,000 miles ; on July 1st, 

 5,000,000 miles ; on July 13th, 12,000,000 

 miles — an increase, after the first of that 

 month, of one-twelfth per day. The tail 

 continued, from its first appearance till the 

 head of the comet ceased to be visible, to 

 point from the latter directly toward the 

 stars Beta and Gamma of the Lesser Bear. 

 Afterward it moved slowly to the westward, 

 so that it covered the dipper of the Great- 

 er Bear. The speed of the particles leav- 

 ing the head to form the tail was estimated 

 as over 3,000,000 miles per day. This 

 brings the particles leaving the comet on 

 July 4th to a distance from its head on 

 July 24th of about 26,000,000 miles, cor- 

 responding at the latter date with the dis- 

 tance of the head of the comet from the 

 earth. But, though the tail thus sweeps 

 over sufficient space to cover the inter- 

 val between the nucleus and the earth, the 

 direction of the tail is such that it fails 

 to reach us ; its central line being dis- 

 tant about 4,000,000 miles, and the edge 

 of the tail about 1,500,000 miles, from the 

 earth." 



Concerning the theory which accounts 

 for the formation of comets' tails by a re- 

 pulsive action of the sun on the matter of 

 the nucleus. Prof. Parkhurst also writes, in 

 the 7'rihme of July 23d : " The existence 

 of a repelling force was suggested by the 

 fact that a comet's tail, pointing eastward 

 when the comet Is east of the sun, points 

 northward and westward as the comet it- 

 self moves around to the north and west of 

 the sun. Yet, as there is no coherence in 

 the tail, it is evident that no repelling force 

 from the sun, when it is to the east of the 

 sun, can have any tendency to bring it 

 around to the west of the sun. The fact 



