Notices respecting New Books, 367 



line, does not belong to helium, because it does not satisfy 

 all the mathematico-spectroscopic criteria of helium-lines. 

 This is also confirmed by the observations made by Prof. 

 Young on August 3 and 5, 1872, in which, at the same time 

 that D 3 , 5015*0, 4571*4, &c, were very strongly disturbed, 

 the lines 4471*2, 7055, and the corona-line 5315*9 remained 

 unaltered. I wish particularly to observe, with reference 

 to the forthcoming solar eclipse, that my calculations and 

 comparisons show that the lines Fievez's 4612*5, 4564*5, 

 Young's 5570, 5450, Tacchini's 4943, 5031, and (what is 

 very important) two lines very near to the magnesium-lines 

 b l and b 2 , belong to helium; the line 7055 (?) very probably 

 to coronium ; lastly, the lines observed May 17, 1882, by 

 Capt. Abney and Dr. Schuster in Egypt (4501, 4473, 4401, 

 4224, 4212, 4195, 4179, 4085, and 4067), as well as at least 

 one of the four red corona-lines (6489, 6492, 6494, 6498), 

 seen simultaneously by Tacchini, viz. 6492 (if not all four), 

 belong to the second compound spectrum of hydrogen. 



The lines seen in the corona by the last-named spectro- 

 scopists and astronomers ought, therefore, in accordance with 

 what has been said above, to originate in the comparatively 

 cooler portions of the corona far removed from the photosphere, 

 in which the elements of hydrogen separated in the hotter 

 regions partly unite to form the common hydrogen, partly to 

 form the ammonium-like hydrogen which produces the second 

 hydrogen-spectrum . 



P. 8. Whilst passing through the press, a new and remark- 

 able confirmation of the wave-lengths of the water-spectrum 

 predicted by me on May 9, 1887, has reached me from Prof. 

 G. D. Liveing, viz. \= 2331*1 to \= 2437*2. 

 Prague, July 17, 1887. 



XLYII. Notices respecting New Books. 



Goal-Tar and Ammonia. Being the Second and enlarged Edition of 

 l A Treatise on the Distillation of Coal-Tar and Ammoniacal 

 Liquor.' By GrEORGE Lunge, Ph.D., Professor of Technical 

 Chemistry in the Federal Polytechnic School, Zurich. London : 

 G-urney and Jackson, 1 Paternoster Row (Successors to Mr. 

 Yan Voorst). 1887. 



WE had occasion to speak favourably of the first edition of this 

 work when it appeared in 1882. At that time it consisted 

 of 383 pages and 88 diagrams ; it now forms a handsome well- 

 printed volume of no less than 739 pages of letterpress and 193 

 diagrams. 



