September 28, 1888.] 



SCIENCE. 



155 



celibacy, but urge, that, when marriage is looked forward to by the 

 deaf, the union of two deaf persons is much surer of being attended 

 with happiness than when one of the party is deaf and the other 

 hearing, and that the slight and doubtful increase of a possible deaf 

 offspring is more than outweighed by the social and personal com- 

 fort. Others draw a distinction between the intermarriages of the 

 congenitally deaf and those who become so in mature years, urging 

 that the probability of deaf descendants is far greater in the former 

 case than in the latter. Many, too, regard consanguinity as a more 

 potent factor in the production of deafness than deafness itself. 

 •Quite otherwise is the verdict given by such scientific men as Cope. 

 Hyatt, Brewer, Newcomb, Brooks, and Bowditch. These, men are 

 unanimous in the opinion that deafness is essentially hereditary, 

 and that the influences now in operation are similar in character to 

 those that a breeder would furnish to bring about a variety with 

 certain characteristics, and that these must tend towards perpetu- 

 ating deafness as a constant characteristic of a certain portion of 

 the human species. As a possible source of light in the matter, 

 the suggestion may be offered that the heredity of deafness may 

 vary greatly with the disease that led to it. So many cases of deaf- 

 ness are due to the after-effects of serious diseases, that here is a 

 possible mode of reconciling the opposite e.xperiences of different 

 observers. 



(4) and (5). Under these heads are given the various usages and 

 modes of instruction in the schools of the country, with a more or 

 less technical discussion of them. 



In general. Professor Bell has succeeded in putting together 

 much valuable matter relating to the deaf-mute class, and the 

 presentation of this pamphlet to the royal commissioners must in- 

 crease their estimation of the work of America in this field of ap- 

 plied science and applied philanthropy. 



NOTES AND NEWS. 



trias and Jurassic of both Europe andJNorth America, the upper- 

 most cretaceous of America, the lowest tertiary of France and 

 America, and probably the post-tertiary of Australia, — truly a re- 

 markable distribution, both geologically and geographically. 



— In his 'Synopsis of the Families and Genera of the North 

 American Diptera,' Dr. VVilliston has rendered a great service to 

 the students of this neglected branch of entomology by bringing 

 together in small compass so convenient and useful a series of 

 tables. Some of these have been given before in different writings 

 of the author, and he has compiled a part from the works of others ; 

 but in no place will the American student find so much comprised 

 in so compact form. By means of it any student with tact can de- 

 termine with considerable certainty to what genus any of his flies 

 belong ; excepting, indeed, in the case of some of the more diffi- 

 cult families which Dr. Williston has not attempted to include, 

 such as the Nematocera and Micscida, the latter the terror of 

 systematists. Dr. Williston has added a bibliography supplemen- 

 tary to that given by Osten Sacken in his useful ' Catalogue of 

 Diptera,' bringing the needed information regarding the literature 

 of dipterology down to date. It should prove a stimulus to the 

 study of the Diptera. 



Among the publications of J. B. Lippincott Company an- 

 nounced as in press, we note ' An Elementary Treatise on Human 

 Anatomy,' by Joseph Leidy ; ' A CyclopEedia of Diseases of Chil- 

 dren, and their Treatment, Medical and Surgical,' edited by J. M. 

 Keating, M.D. ; ' Life of Henry M. Stanley,' by Rev. H. W. Little; 

 and ' Botany,' for academies and colleges, by Annie Chambers- 



Ketchum. Ginn & Co. have in press 'Voices of Children,' a 



theoretical and practical guide on the topic, by W. H. Leib of the 



National Normal Music-School. The October number of Lip- 



piiicot/'s Magazine is a special E. P. Roe number, the first half of 

 which is taken up with articles in one way or another commemora- 

 tive of the dead novelist. The Hon. Hugh McCulloch will dis- 

 cuss in Scribner's Magazine for October, free ships, revenue re- 

 form, immigration, and land-monopoly ; and Prof. Arthur T- 

 Hadley of Yale will contribute an article on 'The Railroad in its 

 Business Relations.' Ginn & Co. are to be the American pub- 

 lishers of the Classical Review, which is published in London, and 

 numbers among its contributors the most eminent classical scholars 

 of Great Britain. American scholars will be associated in the 

 editorship. 



— In a recent valuable and timely monographic paper upon the 

 mesozoic mammals. Professor Osborn of Princeton has shown that 

 the previously entertained views of the paucity of primitive mam- 

 malian life is not so great as has been supposed. No less than 

 thirty-five genera are now known, including five from the trias, and 

 one from what in all probability is correctly considered the most 

 recent cretaceous. That all the vast gap of the cretaceous proper, 

 so rich in vertebrate life, has not yet presented a single mammalian 

 form, is marvellous. Scarcely less remarkable is the fact that 

 among the known forms there is great diversity, the teeth showing 

 si.x or seven wholly distinct types, " and this at a zoological period 

 which we have been accustomed to consider as the dawn of mam- 

 malian life." Further, all these types, though primitive, are essen- 

 tially mammalian, a single genus only showing any reptilian affin- 

 ity. Very interesting, too, are the geographical and geological 

 relationships of the genera. Among the thirteen or more North 

 American Jurassic genera, six have iheir counterparts in English 

 rocks, and the family relationships of all the rest are verj' close. 

 One family, the Plagiaiilacidii:, has its members distributed in the 



LETTERS TO THE EDITOR. 



Recent Changes in the Magnetic Declination in Lower 



California. 



Referring to an interesting note in Science for June 27, in 

 which is given a brief account of magnetic observations lately made 

 on the coast of Lower California and vicinity by officers of the Unit- 

 ed States steamship ' Ranger,' I beg leave to add some remarks 

 further illustrating the change or reversal in the direction of the 

 secular motion as noticed by the observers on the late cruise of the 

 ' Ranger,' at Rosalio Bay. While the fact is here established by 

 direct observations, the phenomenon had already been recognized 

 in a discussion made in the United States Coast and Geodetic Sur- 

 vey Office in January last, and the results were published by per- 

 mission of the superintendent of the survey, at San Francisco, Cal., 

 in the Mining and Scientific Press of Feb. 18, in an article on the 

 ' Magnetic Variation on the Pacific Coast.' Not only the fact of 

 the reversal, but the years of the reversal of the direction of the 

 secular motion, that is, the years when the easterly declination (or 

 so-called ' variation ') ceased to increase and commenced to de- 

 crease, are there given as follows : at San Bias, Mex., in 1856; at 

 Cape San Lucas, Lower California, in 1873 ; at Magdalena Bay in 

 1875 ; and on our own coast at San Diego (Cal.) in 1883. at Santa 

 Barbara in 1880, while at Monterey the reversal is expected about 

 1899. The annual decrease of the declination as given in that ar- 

 ticle is as follows : — 



The fixation of these dates became possible through the discovery 

 by Assistant G. Davidson of the records of magnetic declinations 

 made A. D. 1714 off the coast of Mexico, and transmitted by him 

 to the Coast and Geodetic Survey Office, where they were dis- 

 cussed by Assistant C. A. Schott. 



While the results published in February last supersede those 

 given in the annual report for 1886 (.Appendix No. 12, pp. 290-407), 

 no improvement can be made in the expression for the secular vari- 

 ation of the declination at San Francisco, for which place the cal- 

 culated reversal from increasing easterly to decreasing easterly 

 declination is predicted for 1893. At that time the declination will 

 not sensibly differ from i6''36' east, — its then extreme value. 

 Owing to discord among the individual observations, these pre- 

 dicted years are subject to an uncertainty of several years ; as 

 shown, for instance, in the case of Monterey, for which the calcula- 

 tion appears to assign too late a date. The accurate observations 



