January 23, 1891.] 



SCIENCE. 



5^ 



with them (Mourt's Relation, p. 55 [Dexter's edition] ). William 

 Wood (New England's Prospect, part ii. chap. xvii. p. 101) speaks 

 of them as made of this material : so does the Rev. Francis Hig- 

 ginson ("New England's Plantation," in Young's Chronicles of 

 Massachusetts, p. 357). 



Undoubtedly the Indians found it easier to cut up brass kettles 

 for this purpose than to pound out with their stone hammers 

 pieces of native copper. This they were in the habit of doing, 

 according to Brereton (" Brief and True Relation of the Discovery 

 of the North Part of Virginia," in Collections of Massachusetts 

 Historical Society [3d series], vol. viii. p. 91). 



Henry W. Haynes. 



Boston, Jao. 13. 



Meteorology and Mathematics. 



At a time when the tide of meteorological controversy in your 

 columns runs high and the general outcry is for revision of the 

 old theories, — all apparently because Dr. Hann last spring made 

 some erroneous deductions from observations in the Alps, which 

 has not convinced anybody (vide Hazen), — you may permit me to 

 add my small share to the general conflagration, out of the ashes 

 of which the true Phcenix may some day be expected to rise in all 

 its glory. 



What I here wish to sacrifice on the altar of truth is the so-called 

 mathematical treatment of the circulation of the atmosphere; and 

 I take occasion from a letter by William Perrel in your issue of 

 Jan. 2, wherein the writer complains that Dr. Hann has never 

 attempted to show that his results have been deduced from erro- 

 neous principles or processes. 



I am not aware that any mathematician has ever attempted to 

 show, on rational mechanical principles, what would be the motion 

 of a body of air moving over the surface of a rotating globe, — 

 not over the free and empty surface, but on the bottom of the air 

 universally enveloping and rotating with this globe, being part 

 and parcel of this air itself, — but I think it can be shown, by 

 looking ever so little into the true nature of this subject, that the 

 problem is far more complicated than Professor Ferrel seems to 

 imagine. 



As the speed wherewith places at diflferent latitudes on the 

 earth's surface rotate differ in proportion to their distances from 

 the axis, so it is concluded by Ferrel and others that a particle of 

 air is deflected towards the east when moving towards the poles, 

 and towards the west when moving towards the equator. 



In proportion, however, as the speed of rotation of the particle 

 of air changes while it moves from latitude to latitude, so also the 

 centrifugal force to which it is exposed changes; and therefore, 

 if a change in the former should have the effect of deflecting a 

 current of surface air laterally, so also the effect of the latter must 

 be to deflect the current in a vertical direction. The result hereof 

 is that all pole-bound currents should appear as upper currents, 

 and the surface wind should always be directed more or less 

 towards the equator, and never in the opposite direction. This, 

 however, does not agree with observations. There is a continuous 

 current of surface air round the border of any anticyclone, while 

 in strict consequence of Professor Ferrel's theory we should only 

 expect to find this current round one-half the circiftnference of the 

 high pressure, the other half being deflected into an upper cur- 

 rent. 



According to the way the writer was taught applied mathe- 

 matics (a discipline, by the way, incomparably more diflBcult to 

 master than mathematics itself), it is not admissible to pick out 

 one of the forces acting upon a body in motion, and ignore an- 

 other of equal importance, simply because it does not suit our pur- 

 poses. 



In a paper, " On the Cause of Trade- Winds," read before the 

 American Society of Civil Engineers Dec. 18, 1889 (see "Trans- 

 actions," vol. xsiii. August, 1890), the writer allowed himself to 

 suggest how the gyratory motion of the surface air might be ac- 

 counted for independently of a supposed effect of the earth's rota- 

 tion, which theory, as we have just seen, doesn't bear closer 

 inspection; and one of America's most eminent engineers, Mr. 

 Charles Macdonald, got up at the meeting, and declared the ex- 

 planation given the only rational one he had ever heard, and well 



worth the most careful study. I therefore beg to call the reader's 

 attention to the contents of this paper; and, by comparing my 

 diagrams with the isobaric charts over the North Atlantic for the 

 autumn of 1889, he may see the reason why Dr. Hann found the 

 temperature of the anticyclonic air in the Alps so exceptionally 

 high. Feanz a. Velschow, C.E. 



Brooklyn, Jan. 7. 



The Education of the Deaf. 



Spokien language is the product of the mind enjoined with the 

 enjoyment of all the senses. Its acquisition is facilitated through 

 the sense of hearing, but the latter is not indispensable to it; and 

 to its reproduction by the deaf (without its musical intonation) a 

 normal throat and mouth are requisite. Dr. GOett says, " This 

 [intelligence] the deaf-mute has perfectly" {Science, Dec. 26, p. 

 335). As most of the deaf possess these requirements, the ques- 

 tion that now arises is this: " Is it expedient to invent an artifi- 

 cial sign-language, which of course presupposes articulate speech, 

 in order to impart the latter to the deaf?" Emphatically, no. 

 The oral schools now in existence in this country prove this fact 

 beyond the shadow of a doubt. One of Dr. GUlett's objections is 

 this: "For, while he [the deaf] may utter distinct articulate 

 sounds for others to receive, he cannot receive them himself, and 

 is consequently thrown back upon the visible movements of the 

 superficial parts of the organs of voice, which are chiefly the lips " 

 {Science, Dec. 26, p. 3.57). The deaf will read from the lips- 

 mouth readily when spoken to without voice, that is, mutely; 

 and it is a phenomenon that they are enabled to recognize even 

 the distinction between being addressed audibly and mutely. 

 They will often converse mutely with each other in the school- 

 room, when desirous of not being overheard by then- teacher. 

 Lately one of my patients happened to be a Chinaman. On in- 

 quiring of him what he uses at his meals, — a fork and a knife, or 

 chop-sticks, — he said that at home he uses the latter, but when 

 eating at a restaurant he uses the former. Early education and 

 impressions are lasting. The same is applicable to those mutes 

 who are educated by the combined system, where an artificial 

 sign-language forms the basis of instruction. When a mute edu- 

 cated by that system meets a deaf-mute who was taught by the 

 oral system, the former will naturally address the latter by signs. 

 To start the conversation, the first question perhaps wiU be, ' ' Do 

 you know Mr. P— t ? " The sign for " Mr. P— t " is this: closing 

 the thumb and all the fingers except the forefinger, with which 

 he taps himself at the temple. The other repeats the sign for 

 " P — t," shakes his head, and indicates by expressions that he 

 does not know what this sign means; then the former spells with 

 his fingers the words " P—t, teacher; " and such conversations 

 may occur so often that the one learns the meaning of signs from 

 the other. The deaf educated by the oral system become so am- 

 bitious that they make efforts when in a small circle of society, by 

 constant watchfulness, to follow the connection of the conversation, 

 and try to hide their infirmity. They are even ashamed to use signs. 

 I would gladly go extensively into the details of Dr. Gillett's article 

 on the education of the deaf, but the pressure of professional du- 

 ties will not permit me to devote the time necessary. I would 

 like, though, to direct Dr. Gillett's attention to Hon. Gardiner G. 

 Hubbard's article in Science of Deo. 19, to which I have to make 

 the one exception only, that the first oral school in this country 

 was established in this city, and was in operation in the fall of 

 1864 at No. 427 (old number 415) Eighth Avenue, consisting of two 

 boarding and three day pupils. B. Engelsman. 



New York, Jan. 8. 



BOOK-REVIEWS. 



The Science of Fairy Tales. By Edwin Sidney Hartland. 

 New York, Scribner & Welford. 12°. |1.25. 



This volume is the latest issue in the Contemporary Science 

 Series, and may be described as an attempt to group and classify 

 the various stories of Celtic and Teutonic origin relating to elves 

 and fairies, with illustrations from the stories of other nations. 

 Mr. Hartland opens his work with a fe .v remarks on savage ideas, 



