14 Traxsactioxs of the 



LeptorMoa. ; Filices, Ferns. 



L. mucronatn. Osawatomie. Polj-podiuin. Polypody. 



Eleusine, Yard Gras-s. p jncanum. Burlington. Mrs. J. N. Locke. 



E. Indica. Yard of Presbyterian church, Law- Aspidium, Shield Fern. 



rence. ; a. spimilosum, var. Bootii. Lawrence. Saunders. 



Biichloe, Buffalo Grass. 



* B. dactyloides. Ellis. Watson. | 



A grass called bv this name grows near Osawato- 

 mie, but it seldom or never blossoms, so that it * M. polymorpha. Saunders, 

 would require close observation to determine it. Species added, about ITo. 

 It grows in stools as Butfalo grass is said to, and is >'ot east of the Mississippi, about 27. 

 of about the same size. L.^wre.vce, Kas., Dec. 1873. 



Hepatic.\e. 

 Marcantxia. 



SPECULATIONS IN REGAKD TO COMETS' TAILS. 



BY F. W. BARDWELL. 



Of all questions in Astronomy pressed conspicuously upon notice, none 

 seem to elude the grasp of the scientist with more subtlety than that of the 

 character and composition of comets' tails. From Copernicus to Newton, 

 from Newton to Le Verrier and to the spectroscopist of to-day, are seen a 

 series of brilliant triumphs. The Ptolemaic epicycles have yanished into 

 the simplest of curves ; the multitudinous array of celestial orbs follow each 

 other with infinite precision and never-ending succession, according to laws 

 comprehensible almost by a child. The perturbations of Uranus have 

 responded to the interrogations of Le Verrier and Adams, and our sun and 

 the more distant suns, though they tarry not in their courses at the 

 command of any modern Joshua, yet reveal to the searching gaze of the 

 spectroscopist the secrets of innumerable ages, and declare their common 

 membership of one illimitable system. 



Such are the conquests of astronomers ; and yet an intruder, as it were, 

 rushes impetuously into the insignificant domain of our own solar system, 

 and, it may be, with a passing nod to Jupiter, whirls angrily around the sun, 

 whose pioximitv seems to kindle a fiery train, then retreats as suddenly as 

 he appeared, departing with regal courtesy, never turning the back toward 

 the gaze of his august majesty, the Sun, and at his disappearance leaves the 

 ignorant beholder terrified, and the startled philosopher bewildered. 



Let us glance briefly at the more important facts, and try to find out their 

 significance. Comets are those bodies moving around our sun in orbits of 

 considerable eccentricities. Perhaps this characteristic is the most decisive 

 of those which serve to distinguish them from other members of our solar 

 system, though the classification may really be empirical. There is, indeed, 

 great diversity in the phenomena attending different comets. Some accom- 

 plish their revolutions in three or four years ; others in three or four thousand 

 years ; others still in a hundred thousand years ; and finally, it is thought, 

 some never revisit our solar system. Many comets have tails, so called, 

 while others have none ; and still others are surrounded by envelopes of a 

 hazv or mistv appearance. Some of the so-called tails have been of remark- 

 able extent, and in general have followed the comets in approaching the sun, 



