February 21, 1895 J 



NA TURE 



3Q9 



as those resources are in some instances — we have really an 

 opportunity of doing a considerable amount of work. The 

 particular bit of work which is represented in this diagram is an 

 inquiry showing how the iron lines observed in the spectra are 

 represented in these different stars ; we can see whether the 

 condition of the iron vapour is the same in a star like Arciurus 

 as it is in a star likeyCygni. You will see that from this 

 point of view there is a great difference in the atmospheres of 

 these two stars. 



The definition of the negatives obtained by means of the 

 objective prism is of such excellence that they may be almost 

 indefinitely enlarged, and this gives them a special value when 

 we come to investigate the smaller differences between stars 

 which have more or less resemblance to each other. Practically, 

 we are able to dispense with elaborate micrometric measure- 

 ments, and by placing the enlargements alongside each other, 

 to see at a glance which lines agree in position and which are 

 different. 



NATHANAEL PRINGSHEIM. 



"DOTANISTS throughout the world will have heard, with 

 -^ deep regret, of the death of Prof. Pringsheim on October 

 6, of last year. His name is inseparably a-sociated with the 

 modern progress of the science, and there must be many, who, 

 like the writer of this notice, can trace their first interest in 

 scientific botany, in no small degree, to the fascination of 

 Pringsheim's discoveries. Pringsheim was born in Silesia, in 

 1823. His career, though an active one, was unusually free 

 from official cares. Except during four years, when he was 

 Professor at Jena, he does not appear to have held any teach- 

 ing post of importance. Duiing the greater part of his scientific 

 life, his work was carried on in a private laboratory, founded by 

 himself at Berlin, and devoted entirely to the researches of 

 original workers. 



Pringsheim was founder and editor, from 1858 to the time 

 of his death, of the famous J ahrbiicher fiir Wissenschaftliche 



44 



■15 



1. a CYGKI. 



2. 7 ORIONIS. 



?^W 



i; i 



« If 



■^■^ 



3. o TAURI. 1. a ORIOXI.S. 



• Fig. II. — Portions'of stellar spectra, greatly enlarged.) 



The spectra represented in Fig. 1 1 have been enlarged twelve 

 times from the original negatives, and on this scale the whole 

 of the visible spectrum would be more than a yard in length. 

 Here we observe, in the first place, the immense difference 

 between two groups of stars, one in which the lines are very 

 numerous, the other in which the number of lines is relatively 

 small. We also have an opportunity of studying the more 

 minute differences between stars like a Tauri and those like 

 a Ononis, and between stars like a Cygni and those like 

 7 Orionis. In some cases, differences which might easily be 

 overlooked abotjether in an examination of the negatives alone, 

 become apparent when the scale is enlarged in this way. 



Thus, by n cans of the aids which have been placed at our 

 disposal, by the recent improved condition of our stock in trade, 

 and the wonderful diligence and skill of observers, chiefly in 

 America, who have taken up the new work, we are now in a 

 very much lietter position than we have ever been before to 

 investigate this subject. J. Norman Lockver. 



(7(7 bi continued.) 



Botanik, and was President of the German Botanical Society 

 from its first origin. He was among the many distinguished 

 foreign men of science who attended the meeting of the 

 Biitish Association at Manchester, in 1S87. 



The scientific activity of Pringsheim extended over a period 

 of fully forty years (1S48-18S8), a time which covers what was 

 perhaps the most brilliant epoch in the history of botany. His 

 »oik began in the days when the science of histology was 

 being built up on the basis of the cell-theory of Schleiden and 

 Schwann ; he himself contributed essentially to its construction. 

 Piingsheim's greatest services to science, however, were in the 

 department of the morpholrgy and life-history of the lower 

 plants, a line of research in which he was unsurpassed. Com- 

 paratively late in life his attention became directed to physio- 

 logy, but in this direction his success was less conspicuous. 



Pring'-heim's earliest contribution to science was his 

 Latin disseitation, " De forma et incremenio straiorum 

 crassiorum in plantarum cel)ul;i" (Linncca, 1S48), in which he 

 discusses a question much agitated at that time, whether the 



NO. 132 1, VOL. 51] 



