312 



NATURE 



\^Fch. 15,1872 



and under the management of Prof. Henry Draper, containing a 

 report " on the chemical and physical facts collected from tlie 

 Deep Sea Researches made during the voyage of the nautical 

 school-ship Mti-diry, undertaken in the Tropical Atlantic and 

 Caribbean Sea in 1S70-71 ; the "cruisers " being, not Dr. Car- 

 penter, Prof. Wyville Thomson, and Mr. Gwyn Jeffreys, Imt 

 the boys committed to the care of the Commissioners in New 

 York for slight misdemeanours and vagrancy ! 



We regret to hear that tlie Geology Class at Christ's Hospital, 

 having gone through an introductory course of lecture.', hjs 

 stopped, and has not been replaced by a class of Botany or any 

 sister science. It is greatly to be regretted that the Chemistry Class 

 do not get beyond the simpler metals and easy testing ; those who 

 would wish to study Chemistry are restricted to the more 

 elementary branches of inorganie chemistry alone. 



Prof. Hughes, F.R.G.S., gave two lectures at Christ's 

 Hospital on February 3 and 10 on Physical Geography. In his 

 introduction he, like Prof. Huxley, claimed for his science a posi- 

 tion equal to that held by the German Erdkunde, defining both 

 to be that which explained to us "the aspect of nature and 

 natural phenomena." In his first lecture he dealt with "High 

 Lands and Table Lands," somewhat overthrowing the popular 

 idea of mountains gained from text books. In his second lecture 

 he spoke of the " Ocean and Deep-Sea Currents," explaining 

 clearly and advocating warmly the ingenious theories and proofs 

 of Dr. Carpenter, about which there h.is been so much discus^ion 

 in the pages of Nature. We attach no little importance to 

 these lectures, because tliey brouglU the hearers up to the present 

 state of our knowledge of the deep sea and of the Himalayan 

 Mountains, far further than the best te.xt-books have yet 

 brought us. It is only to be regretted that other gentle- 

 men of like abiliiies and knowledge with Prof. Hughes do not 

 come forward and offer to lecture to boys on other branches of 

 Natural Science. It is hard for those who feel an interest in 

 nature to feel themselves bound by the iron chains of verse com- 

 position. 



LippiiiCi'll's A/,7^ir:iiii- for January contains an interesting and 

 profusely-illustrated article on the New Port Storm Signals, l)y 

 Prof. Thompson Pj. Maury. 



p//rs/cs 



Preliminary Catalogue of the Bright Lines in the 

 Spectrum of the Chromosphere* 



The following list contains the bright lines which have been 

 observed by the writer in the spectrum of the chromosphere 

 within the part four weeks. It includes, however, only tliose 

 which have been seen twice at least ; a number observed on one 

 occasion (.Sept. 7) still await verification. 



The spectroscope employed is the same described in the Jour- 

 nal of the Franklni Institute for November 1S70 ; but certain 

 important modifications have since been effected in the instrument. 

 Tlie telescope and collimator have each a fo :al length of nearly 

 10 inches, and an aperture of ; of an inch. The pnsm-train 

 consists of five prisms (with refracting angles of 55°) and two half- 

 prisms. The light is stnt twice through the whole series by 

 means of a prism of total reflection at the end of the train, so 

 that the dispersive power is that of twelve prisms. The instru- 

 ment distinctly divides the strong iron line at 1961 of Kirchhoff 's 

 scale, and separates B (not b) into its three components. Of 

 course it easily shows everything that appears on the spectrum 

 maps of Kirchhoff and Angstrom. Tne adjustment for "the 

 position of minimum deviation" is automatic ; i.e., the different 

 portions of the spectrum are brought to the centre of the field of 

 view by a movement which at the same time also adjusts the 

 prisms. 



* Reprinted from the A mcricfin yoiirnal 0/ Science and A rts. 



The telescope to which the spectroscope is attached is the new 

 equatorial recently mounted in the observatory of the College by 

 Alvan Clark and Sons. It is a very perfect specimen of the 

 admirable optical workmanship of this celebrated firm, and has an 

 aperture of 9,^ inches, witli a focal length of 12 feet. 



In the table the first column contains simply the reference 

 number. An asterisk denotes that the line affected by it has no 

 well-marked corresponding dark line in the ordinary solar spec- 

 trum. 



The second column gives the position of the line upon the 

 scale of Kirchhoff's map — determined by direct comparison with 

 the map at the time of observation. In some cases an interroga- 

 tion mark is appended, wliich signifies not that tlie existence of 

 the line is doubtful, but only that its precise place could not be 

 determined, either because it fell in a shading of fine line«, or 

 because it could not be decided in the case of some close double 

 lines which of the two components was the bright one ; or, 

 finally, because there were no well-marked d.aik lines near enough 

 to furnish the basis of reference for a perfectly accurate deter- 

 minition. 



The third column gives the position of the line upon Ang- 

 strom's normal atlas of the solar spectrum. In this column an 

 occasional interrogation mark denotes that there is some doubt 

 as to the precise point of Angstrom's scale corresponding to 

 Kirchhoff's. There is considerable difference between the two 

 maps, owing to the omission of many faint lines by Angstrom, 

 and the want of the fine gradations of shading observed by 

 Kirchhoff, which renders the co-ordination of the two scales 

 sometimes difficult, and makes the atlas of Kirchhofif far superior 

 to the other for use in the observatory. 



Tlie numbers in the fourth column are intended to denote the 

 percentage of frequency with which the corresponding lin s are 

 visible in my instrument. They are to be regarded as only roughly 

 approximative ; it would of course require a much longer period 

 of observation to furnish results of this kind worthy of much 

 confidence. 



In the fifth column the numbers denote the relative brilliance 

 of the lines on a scale where 100 is the brightest and I the (aintest. 

 These numbers also, like those in the preceding column, are 

 entitled to very little weight. 



