1074 Transactions of the American Institute. 



Solar spots appear singly or in groups within thirty degrees of the 

 sun's equator, and from their position are supposed to be directly 

 influenced by the rotation of the sun. They expand, contract and 

 disappear with great rapidity, yet their peculiar formation precludes 

 the idea entertained by some that the same s])ot can ever return. 

 These spots are found unusually numerous in certain intervals of 

 time. The veteran observer, Schwabe, of Dessau, who has for the 

 last forty years made this subject his constant study, gives to sun 

 spots a periodicity of eleven years, an4 has suggested that they may 

 have some connection with meteoric showers. Prof. Wolfe, sometime 

 since, expressed an opinion in the Paris Conqjies Itendus that their 

 appearance dej^nded on the planets, Saturn, Jupiter, Venus and the 

 eartli. It has not yet, however, been satisfactorily shown that there 

 is any direct relation between their periodicity and that of any other 

 celestial phenomenon. So much is yet to be discovered before the 

 problem of sun spots can be solved that the sun must remain for a 

 long time the most interesting day study of the astronomer. The 

 iigitation of the sun's exterior is a subject of special wonder. Obser- 

 vations frequently made during a solar eclipse prove that portions of 

 ihe gaseous exterior rise, as protuberances, to the height oF 80,000 

 miles beyond its apparent surface. Many of the solar spots are known 

 to exceed 50,000 miles in diameter and 2,000 miles in depth, while in 

 the immediate neighborhood of the great spots the telescope reveals 

 the movement of most luminous streaks called faculce, and every- 

 where minute specks and pores which seem to be kept by the seeth- 

 ing mass ill constant fluctuation. Certainly, the most sublime idea of 

 commotion which can be conceived will be derived from a study of 

 that vast and incessant sweep of attenuated matter which forever 

 varies, and yet preserves the form of the sun's surface. 



The Velocipede. 



Mr. John Johnson exhibited and explained a diagram illustrative of 

 some points connected with the velocipede. The question involved 

 seemed to relate to the power of a man as applied to such a machine, 

 and measured in foot-pounds. « 



Mr. J. K. Fisher read from his note-book the results of certain 

 investigations recently made in regard to the velocipede as a useful 

 machine ; that is, as one which accomplishes a fair amount of work 

 in proportion to the amount of power applied. Referring to the 

 experiments of Sir John McNeill in regard to traction on roads of 



