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THE POPULAR SCIENCE MONTHLY. 



thing that is going on in this world. It 

 underlies agriculture ; it is the basis of 

 manufactures ; it is the key to geology ; 

 meteorology depends upon it ; it explains 

 domestic processes ; is the foundation of 

 physiology and biology, and, moreover, as- 

 tronomy has lately courted its alliance, and 

 arrived at the most splendid results by its 

 aid. Certainly a magazine which chroni- 

 cles the progress of this most progressive 

 of the sciences should have a vigorous 

 support, while the reputation of its accom- 

 plished editors is the best guarantee of its 

 trustworthy character. 



MISCELLANY. 



The New Planet Vnlcan. The observa- 

 tion of certain disturbances in the motion 

 of the planet Mercury, and the appearance 

 :it particular periods of well-defined circular 

 black spots, passing rapidly across the disk 

 of the sun, have led astronomers to suspect 

 the existence of a ninth planet, interior to 

 Mercury, and with a period of revolution, 

 according to M. Leverrier, of 19.70 days. 

 Such a spot was seen to cross the sun on 

 March 26, 1859, the observer being a French 

 physician named Lescarbault, who there- 

 upon claimed the discovery of the planet, 

 to which the name of Vulcan was assigned. 

 It should be added, however, that other ob- 

 servers had previously witnessed a similar 

 phenomenon. The spot was again seen by 

 Mr. Lummis, of Manchester, on the 20th of 

 March, 1862. From calculations based upon 

 these and other observations, Mr. Hind, of 

 the Twickenham Observatory, England, in 

 a letter last year to the London Times, sug- 

 gested 10 o'clock a. m. on the 24th of 

 March, 1873, as the time when a conjunction 

 of the supposed planet with the sun might 

 be expected to occur. " If the hypothetical 

 body," says Mr. Hind, " is not found upon 

 the sun's disk at that time, it will be, I think, 

 a sufficient proof that my surmises are in- 

 correct." Prof. Kirkwood, in a recent letter 

 to the Tribune, states that " Mr. Cowie has 

 just reported the appearance of such a spot 

 on the sun at Shanghai, China, on the morn- 

 ing of March 24, 1873, thus fulfilling the 

 prediction of Mr. Hind, and rendering the 

 existence of such a planet reasonably cer- 

 tain. Prof. Kirkwood's calculations, as given 



in the letter above quoted, make its sidereal 

 period 34 days, 22 hours, 31 minutes. In 

 a subsequent letter, Prof. Kirkwood calls 

 attention to the fact that similar spots have 

 been observed on the sun, at other dates, 

 which cannot be referred to the same aste- 

 roid, and he thence infers the existence of a 

 zone of minor planets within the orbit of 

 Mercury. Why none of these have ever 

 been seen during total eclipses of the sun 

 he explains as follows : 



" It is well known that a marked differ- 

 ence obtains between the light-reflecting 

 capacities of the various planets of our sys- 

 tem. Mercury, for instance, is in this re- 

 spect very much inferior to Venus and Ju- 

 piter. (See Proctor's " Other Worlds than 

 Ours," p. 67.) The difficulty, then, in re- 

 gard to the invisibility of these asteroids 

 when the sun is eclipsed, may be obviated 

 by supposing their surfaces so constituted 

 as to reflect but a small portion of the sun's 

 light." 



Education in Sierra Lccne. Mr. John 

 Pope Hennessy, ex-Governor of Sierra Leone, 

 delivered recently, before the London Society 

 of Arts, an admirable lecture on " the Brit- 

 ish Settlements in Western Africa." We 

 give a synopsis of that part of the discourse 

 which treated of the state of education. It 

 is the avowed purpose of the British Gov- 

 ernment to train the natives to habits of 

 self-control, so that they may be finally suf- 

 fered to govern the country themselves. 

 But that no great progress has been made 

 in the preliminary work of education is ad- 

 mitted on all sides. In 1869, " education 

 was most inadequately provided for" in 

 Sierra Leone. In 1870 the " conspicuous 

 listlessness and inattention of the scholars " 

 are noted by the Director of Public Instruc- 

 tion. In 1872 Mr. Hennessy was himself 

 convinced that the system in use was only 

 " an incentive to the formation of a thought- 

 less, idle, and indolent character." And at 

 Cape Coast matters were still more unprom- 

 ising. In 1872 the government chaplain 

 calls loudly for compulsory education, be- 

 cause he cannot induce the scholars to at- 

 tend to their duties. 



That the fault does not lie with the na- 

 tives is very satisfactorily shown by Mr. 

 Honne6sy. On his second visit to Lagos, 



