368 



SCIENCE. 



[Vol. IV., No. 89. 



been more lying about storage-batteries in gen- 

 eral, during the last few years, than about any 

 other commercial scheme before the public. 

 Thus far, these batteries do not appear very 

 prominently in this country. In view of the 

 novelty and importance of the subject, both 

 scientifically and commercially, it is to be 

 hoped that the competing s} r stems may be sub- 

 mitted to thorough tests by the boards of ex- 

 aminers of electrical exhibitions. 



LETTERS TO THE EDITOR. 



*** Correspondents are requested to be as brief as possible. 

 The writer's name is in all cases required as proof of good faith. 



Minerals near Philadelphia. 



Permit me to call Philadelphia mineralogists' at- 

 tention to a new locality for garnets and green musco- 

 vite. The garnets are found in a small quarry of 

 talcose rock, about one mile below Lafayette station, 

 on the Pennsylvania and Susquehanna valley rail- 

 road. The quarry is a short distance below the soap- 

 stone quarry, and on the edge of a small stream. The 

 garnets are very fine in color and shape. Green mus- 

 covite occurs plentifully a few hundred feet below the 

 garnets in the side of the ratt way-cut. 



Joseph T. Meehan. 



Philadelphia, Oct. 6. 



The Delaware estuary. 



In your notice (No. 86) of the 'Estuary of the Del- 

 aware,' you erred in the authority for the surveys. 

 The hydrography upon which the study was based 

 was executed by H. L. Marindin, Lieut. H. B. Mans- 

 field, and Lieut. E. B. Thomas, assistants in the coast 

 and geodetic survey. J. A. Sullivan. 



Boston, Sept. 27. 



[We thank our correspondent for calling our atten- 

 tion to what was an accidental omission in our notice 

 of the recent report of the coast-survey study of the 

 ' Estuary of the Delaware.' —Ed.] 



American pearls. 



I beg leave to ask the assistance of the readers of 

 Science in gaining information regarding the finding 

 of American pearls in either fresh or salt water; also 

 the weight, color, lustre, and value of the same, with 

 the name of the mollusk in which they were found, 

 and date of finding. 



A preliminary paper on this subject was read at 

 the Philadelphia meeting of the American association. 

 The paper will be published in full by the U. S. fish- 

 commission. Due credit will be given for any in- 

 formation. George F. Kunz. 



With Tiffany & Co., New York, Oct. 6. 



A wider use for scientific libraries. 



I noticed in the last number of Science a propo- 

 sition to render the libraries of the various scientific 

 societies more useful by circulating the books some- 

 what by mail, among persons located in small towns. 



If those having charge of those libraries knew what 



a blessed boon such an arrangement would be to a 

 man situated as I have been for a few years, I am 

 sure they would heartily second the proposition. Col- 

 leges are often located in small towns, and are very 

 poorly supplied with the means for scientific study 

 or investigation. Professors in such institutions 

 would be delighted with any arrangement, not in- 

 volving very great expense, which would give them 

 access in any way during term-time to a good scien- 

 tific library. Would not some such arrangement as 

 this be a wise one? — Require a person wishing for 

 the privilege of taking books from the library to give 

 bond for a sum sufficient to meet all possible liabili- 

 ties, and charge to his account all the actual expenses 

 incident to packing and mailing or expressing books 

 to him, and also any books not returned. Charge 

 him, also, a small annual fee for the use of the books. 

 In that case, he would pay only the actual expenses, 

 and for the use of the books. 



I earnestly hope our scientific societies may con- 

 sider this question, and give to those of us who are 

 isolated from the rest of the world, in small colleges 

 and small towns, the benefit of the wealth of learn- 

 ing idly hoarded up in their libraries. 



W. Z. Bennett. 



Wooster, Wayne county, O., 

 Oct. 7. 



Systematic earthquake observation. 



The mention of my name in several recent articles 

 in your columns and elsewhere may excuse the seem- 

 ing egotism of the proposal which is the object of this 

 letter. 



I am much interested in the recent suggestions 

 of Science looking toward the closer intercourse of 

 those who are interested in practical seismology. 

 We have not in the United States, at least in the 

 eastern part, any such promising field for observa- 

 tional work as that occupied by the Seismological 

 society of Japan; and the number of persons at pres- 

 ent interested in the study is not large, perhaps too 

 small to make advisable the formal organization of a 

 seismological society. But my records, kept now for a 

 dozen years, make it quite evident that earthquakes, 

 even on the Atlantic seaboard, are by no means such 

 infrequent phenomena as is generally supposed; and 

 I am convinced that systematic instrumental obser- 

 vation would largely increase the number by the de- 

 tection of minor shocks and tremors which now pass 

 entirely unrecognized and unsuspected. 



As to the second point, also, it is quite probable 

 there may be more persons interested in the subject, 

 and willing to do some work for it, than are known to 

 me. In the effort to find out the number and the 

 names of such persons, I am quite willing to serve 

 as the medium of communication for the present; 

 and I would therefore venture to suggest that all 

 such persons communicate with me, either through 

 your columns or by mail directly, with the view of 

 ascertaining whether we are sufficiently numerous to 

 make concerted observational work possible and de- 

 sirable. C. G. Rockwood, jun. 



Princeton, N.J., Oct. 10. 



The prime meridian. 



Permit me to add to your remarks in No. 88 of 

 Science, concerning the present confusion resulting 

 from too many initial meridians, a few facts from a 

 recent German periodical. The ' nautical almanacs ' 

 published by England, Germany, France, and the 

 United States, refer, in part at least, to the meridians 



