March 13, 1891.] 



SCIENCE. 



143 



that is to say, a region, rising roughly from 3,000 to 3,000 feet 

 above the snow-line, generates a glacier which descends more 

 than 2,000 feet below it. 



But what change is required to give a glacial epoch to Switzer- 

 land ? It is generally agreed that an ice-sheet has enveloped the 

 whole of the lowland region between the Alps and the Jura. Let 

 us assume, that, other conditions remaining the same, this could 

 occur if the mean annual temperature of this lowland were 

 reduced to 33°. Its present mean temperature varies somewhat; 

 for instance, it is 4.5.86° at St. Gall, 49.64° at Lausanne. Let us 

 take 47.5° as an average, which is very nearly the mean tempera- 

 ture of Lucerne. ' So this lowland requires a fall of 15.5°. We 

 may take the average height of the region as 1,500 feet above the 

 sea. If, then, we begin the effective gathering-ground at 1,000 

 feet higher, the valley of the Reuss from well below Wasen, and 

 the valley of the Rhone from a little above Brieg. would be buried 

 beneath neve: so thac probably a fall of 16° would suffice to cover 

 the lowland with an ice-sheet, and possibly bring its margin once 

 more up to the Pierre-a-hot above Neuch&tel; at any rate, a fall 

 of 18° would fully suffice, for then the mean temperature of Ge- 

 neva would be slightly below 32°. 



The line of 41° passes through Scandinavia a little north of 

 Bergen. If, then, the climate of Norway were lowered by the 

 same amount, which also is that suggested for Britain, the temper- 

 ature at this part of the coast would be 23°, corresponding with 

 the present temperature of Greenland rather south of Godhavn, 

 and probahly no part of Norway would then have a higher mean 

 temperature than 26°. 



The wants of North America are less rather than greater; 

 though, as geologists affirm, an ice-sheet formerly buried all the 

 region of the Great Lakes, and descended at one place some fifty 

 leagues south of the 40th parallel of latitude. Its boundary was 

 irregTilar; but, if we strike a rough average, it may be taken as 

 approximately corresponding with the present isotherm of 50°. 

 The temperatures, however, in North America fall rather i-apidly 

 as we proceed northwards. Montreal is very nearly on the iso- 

 therm of 45°, and this passes through the upper part of Lakes 

 Huron and Michigan; that of 39° runs nearly through Quebec and 

 across the middle of Superior; while at Port Arthur, on the same 

 lake, the temperature is only 36.2°. If, then, we assume sufficient 

 precipitation, the maximum fall of temperature required for this 

 North American ice-sheet will be 18°; but less would probably 

 suffice, for the district north of the St. Lawrence would be a favor- 

 able gathering-ground. This would be brought within the iso- 

 therm of 32° by a fall of 12°, or, at most, of 13°. 



It seems, then, that if we assume the distribution of temperature 

 in the northern hemisphere to have been nearly the same as at 

 present, we require it to have been lowered, at any rate in the 

 regions named, by about 18°, in order to bring back a glacial epoch. 

 For North Wales a reduction of about 20° might be needed; 

 but, if the isotherms ran more nearly east and west, 18° for the 

 Thames valley might suffice. If we assume the great extension 

 of glaciers in central and north-western Europe to be contempo- 

 raneous with that in America, we must suppose that these parts 

 of the northern hemisphere had a climate more nearly resembling, 

 but even colder than, that which now prevails in the southern 

 hemisphere. The isotherm of 40' runs a little to the south of 

 Cape Horn: that of 45° passes north of the Straits of Magellan. 

 The latter lie on parallels of latitude corresponding with those of 

 North Wales, but their mean temperature is about 8° lower. If 

 we could restrict ourselves to the British Isles, it would be enough 

 to assume a different distribution of temperature from that which 

 now prevails on the globe, for at the present time, and in the 

 northern hemisphere, the isotherm of 33° twice comes down very 

 nearly to the latitude of London; but it may be doubted whether 

 this alone would account for the great extension of the Alpine 

 glaciers, and the difficulties seem yet greater in the case of North 

 America. Here, where even at present the temperature is rather 

 abnormally low, we have to make a verj' considerable reduction. 

 But this is too wide a question to discuss at the end of an article 



' St. Gall, 45.86° P.; Berne, 46.58°; Lucerne, 47.48°; Zurich, 48.20°; Neacha- 

 tel, 48.74°; Geneva, 49.46°; Lausanne, 49.64°. St. &all and Berne are rather 

 high stations, the one being 2,165 feet, the other 1, L v ji i \ The lak« of Lu 

 c^rue is 1,437 feet above the sea. 



in these pages. We seem, however, fairly warranted in conclud- 

 ing that, whatever may have been the cause, a lowering of tem- 

 perature amounting to 18°, if only the other conditions either 

 remained constant or became more favorable to the accumulatioQ 

 of snow and ice, would suffice to give us back the glacial epoch, 



T. G. Bonnet. 



A NEW DEPARTURE IN DEAF-MUTE EDUCATION. ' 



The attention of instructors of the deaf and their friends has in 

 various ways within the past few months been called to a pro- 

 posal, very briefly outlined in the annual report of the Columbia 

 Institution, for the enlargement of the facilities for normal train- 

 ing already existing in this college. 



Misapprehensions have naturally arisen as to what was proposed, 

 because, in the absence of any official utterance, unauthorized per- 

 sons have taken it on themselves to publish conclusions based purely 

 on presumptions, or, In some instances, on incomplete statements 

 and perverted inferences. 



As the plans of our directors for the "new departure" are now 

 measurably complete, final action having been only reached in a 

 meeting of the board held this day, I take pleasure in announcing 

 that the teaching force of our institution will be increased next 

 year by the employment of an experienced instructor in articula- 

 tion, who will be especially devoted to the promotion of speech 

 and lip-reading in the college. 



Liberal provision has recently been made for this object by 

 Congress. 



The directors have to-day established six normal fellowships, of 

 the value of five hundred dollars each per annum, to which grad- 

 uates of colleges will be appointed for one year. These fellows 

 will be required to reside in the institution, and will receive in- 

 struction in both the manual and the oral methods of teaching the 

 deaf. They will, in view of the advantages to inure to them from 

 these fellowships, be expected to perform certain duties in the 

 institution, and will therefore constitute a distinct addition to its 

 teaching force. 



The funds for sustaining these fellowships are at the disposal 

 of the board from sources other than the treasury of the United 

 States. 



The suggestion of establishing these fellowships, with a view of 

 training instructors of the deaf of the highest grade, is taken from 

 the arrangement existing in the Johns Hopkins University at Balti- 

 more, from the ranks of whose fellows college professors, princi- 

 pals of high schools, and other instructors of high rank, arc drawn 

 in large and increasing numbers. 



Johns Hopkins University, 



Baltimore, Md., March 5, 1891. 

 Dr. E. M. GaI/Laudet, 



President National Deaf-Mute College. 



Dear Sir, — I am very much interested in what you have told me 

 of your plans and hopes for the development of the National Deaf- 

 Mute College. Particularly it seems to me wise that you should 

 give prominence to the fact that articulation is taught, by designat- 

 ing a competent instructor who should have a specific title indi- 

 cating that he performs this service. I ara even more interested in 

 what you say of the possibility of enlisting annually half a dozen 

 or more men in the service of the college, who would not only be 

 valuable assistants during their residence with you, but would be 

 trained for permanent careers in the various institutions of the land. 

 Such a system here has been most fruitful in good results, and I 

 can easily foresee how a carefully choseu staff of associates or fel- 

 lows in the National Deaf-Mute College, holding an intermediate 

 position between the permanent members of the faculty on the one 

 hand, and the students on the other, would inspire the teachers, 

 help the scholars, and furnish, in time, a corps of instructors for 

 the schools for the deaf, which now exist in such considerable num- 

 bers throughout the country. 



Yours sincerely, 



D. C. Giljian. 



The above letter from President Gilman had much weight 

 with our directors in their deliberations to-day. 



' Circular of Information Issued by the National Deal-Mute College, Wash- 

 ington, D.C., March 7, 1891. 



