April 21, 189G ] 



SCIENCE. 



617 



geology should be fit to advise in regard to 

 a mining venture. The teacher may be an 

 expert in the economics of the profession, 

 but the proof of the fact is not to be found 

 in his scientific work or in his success as 

 an instructor. If he has not had the other 

 training it may be safely assumed that he 

 will be totally unfitted to wrestle with the 

 tricky fellows who try in amazingly varied 

 ways to deceive him, or even with the ten- 

 dencies of his own mind, which naturally 

 lead him to see riches where others fancy 

 they discern them. 



In the interests of our science it is most 

 desirable that all expert work should pass 

 into the hands of a body of men who should 

 bring to their task so much of geology as is 

 needed for the particular inquiry, commonly 

 not very much, and who can join with it 

 the more important practical acquaintance 

 with the miner's art and the conditions of 

 trade which relate thereto. In certain cases 

 the men of theory may well serve these ex- 

 perts ; all their inquiries are likely to be of 

 service in the determinations, but on them 

 should not be the responsibility for the 

 business side of the problems. There is 

 little the geologist does in the way of re- 

 search which may not have some practical 

 application to the affairs of men, but he 

 should not mistake this possibility of use- 

 fulness as an indication that it is for him 

 to give his inquiries an economic turn. 



CONCLUSION. 



"We thus see that geological science, like 

 the most of the other branches of natural 

 learning, has two distinct points of contact 

 with society — that of instruction and that 

 of economic affairs. In each of these fields 

 of usefulness its services to man have been 

 great and are to be far greater in the time 

 to come. As for instruction, the task is to 

 give to men an adequate perspective for 

 their lives. It is to ennoble our existence 

 by showing how it rests upon the order of 



the ages. In the economic field it is to 

 show the resources which these ages have 

 accumulated in the earth for the service of 

 the enlarged man, who is to attain his pos- 

 sibilities by a full understanding of his 

 place in nature. To do the fit work we 

 need to combine the functions of explorers 

 and guides zealous to open the way to the 

 unknown, and those of teachers who take 

 care that the youth of our time are led 

 into the land which we kuow to have so 

 much promise for man. 



SOME VALUES OF STELLAR PARALLAX BY 

 THE METHOD OF MERIDIAN TRANSITS. 

 In this article are presented values of the 

 parallax for thirteen of the list of nearly 

 ninety stars upon which I have been en- 

 gaged at this observatory the past two years. 

 The results here given include the values 

 presented at the Springfield meeting of the 

 American Association for the Advancement 

 of Science, with some additions. They are 

 the results of preliminary solutions based 

 upon all my observations of these stars 

 available at the time, and equal weight has 

 been given to each observation. 



The method employed is that of the dif- 

 ferences of meridian transits, and it is be- 

 lieved this is its first application since it 

 was introduced in its present detail by Prof. 

 Dr. J. C. Kapteyn at the Leiden Observa- 

 tory in 1885-87. He determined the paral- 

 laxes of fifteen stars by this method with a 

 high degree of accuracy. The observing 

 consists in noting the successive times of 

 transit of three stars, of which the first and 

 third are comparison stars and the middle 

 star is the one whose parallax is sought. 

 The former should be so chosen as to make 

 the group of three stars as symmetrical as 

 possible in both position and magnitude. 

 Of course, a fine meridian instrument is re- 

 quired, and for the present series the Eep- 

 SOLD meridian circle of 12.2 cm. was em- 

 ployed with a power of 180 diameters. To 



