2I5 



;5ClKi\CE. 



[Vol. XX. No. 506 



your and yore are classed as identical in sound. Your, shore, and 

 drawer are thus ■' phoneticised" into yawer, shawer, and drawer. 

 These words are, indeed, often so pronounced in dialectic speech; 

 but the science of phonetics must be retrograding instead of ad- 

 vancing when, in an "Introductory Science Text-Book," such 

 differences can be ignored, and such mere negligences cited as 

 examples of correct usage. 



All short vowels stop sharply on consonant-R, as on other con- 

 soaants, as in parrot, very, spirit, sorry, hurry; but long vowels 

 take on the connective glide even before consonant-R, as in 

 weary fairy, iviry, gory, fury. Thus wea(j)ry, fai(a)ry, wi(a)ry, 

 etc. 



The vowel quality inherent in the mouth-cavity of R is that of 

 er-ir in her. sir. Consequently, in such words a.'iflrm, yearn, the 

 r has the effect of lengthening the syllable by making it contain 

 two sounds of the same vowel. Let us put the words under the 

 microscope : — 



fi (a)rm; 3'ea (a)rn. 



Test this further by analyzing the syllable "word." If the r 

 were "silent," the vowel would be sharply stopped by the con- 

 sonant d. Thus, wo d; bat the trae proaunciatiou of this 



syllable interposes a glide between tbe vowel and the d. Thus, 

 wo (a)rd. 



In forming this smooth transitional r the tongue is ^slightly 

 lifted from the bed of the jaw; therefore when a vowel follows 

 tbe r, the consonant sound of the letter is also developed; as in 

 fe iring = fear ring There is a tendency among many speakers 

 to finish all open vowels with this lift of the tongue, so that the 

 consonant r is inadvertently interpolated between two words, as 

 in "'Pennsylvania-r-Avenue, " I saw-r-it all." 



Nice distinctions — like those which are the subject of this 

 pa;jer — are of no importance where mere intelligibility is con- 

 cerned; for example, in the speech of the deaf. In such cases, 

 the widest differences may be disregarded, so long as the words 

 are understood. But in the study of phonetics, the most minute 

 varieties require to be distinguished, because what in one case 

 m ly be a distinction with but little difference, may in another be- 

 come a very shibboleth. 



I make no apology for introducing so small a topic to your 

 attention. In a practical subject nothing is too small to be care- 

 fully investigated. The whole organism of speech is but small, 

 and the differences of organic action from which the greatest 

 elementary distinctions result are, in actual measurement, exceed- 

 ingly small. 



The sounds of R, with all their differences —rough, smooth 

 guttural, lingual, labial, definite, indefinite — are only one in 

 kind ; and we must recognize them in their faintest as well as in 

 their most obtrusive forms. 



ON THE SECULAR MOTION OF A FREE MAGNETIC 

 NEEDLE.' 



BY L. A. BAUER. 



A MAGNETIC needle suspended so as to move freely in all direc- 

 tions will set itself tangent to the lines of terrestrial magnetic force. 

 At any particular epoch it will have a definite direction. It wil 

 jnake a definite angle with the meridian, which, measured in the 

 horizontal plane, is known as its declination, also a definite angle 

 with this plane, which, measured in the vertical plane, is termed 

 its inclination or dip. About this mean position of equilibrium a 

 variety of small periodic variations take place, accompanied at 

 times by fitful or irregular ones, which occasionally become quite 

 respectable. Concerning this we shall have nothing to say. But 

 the needle undergoes another, and by far the largest excur- 

 sion, requiring centuries for its fulfilment. Since its discovery 

 in 1634 by Gellibrand, as exhibited in the secular variation of one 

 of its co-ordinate angles, the declination, it has been the cause 

 of no end of fruitless speculation. It has engaged some of the 



> Abstract of a paper read before Section A of the A.A.A.S., Aug. 18, 1892. 



best minds and given rise t ) most ingenious theories, but the rid- 

 dle is still unsolved. 



As the needle assumes different positions for different epochs, 

 it gradually sweeps out in space a cone, whose vertex is the 

 centre of gravity of the needle. Or, if you describe a sphere 

 having as a centre the centre of gravity of the needle, and pro- 

 long the axis of tbe needle until it intersects the sphere, the, suc- 

 cessive intersections will form some tortuous curve. The geome- 

 tric nature of this cone, or of this tortuous curve, remains to be 

 investigated. A preliminary analytical attempt was made by 

 Quetelet in 1877. He used fifty years of continuous observations 

 of declinations and dip made at Brussels, and found that a cone 

 of revolution would best fit his observations, the period of a com- 

 plete revolution being .113 years." .Mr. Sohott made a graphical 

 attempt for an average New England station, using about fifty 

 years of observation. The scantiness of his material prevented 

 him from making any safe deduction as to the course of the 

 needle.' 



To our knowledge, however, no attempt has as yet been made 

 for the long series of observation which we possess at quite a 

 number of stations The usual custom is to discuss separately the 

 secular variation of the different magnetic elements, as though 

 they were different effects of forces acting, instead of component 

 effects. We balieve that this, in some measure, is the reason that 

 with 100-300 years of observation no greater headway has been 

 made in the conception of the requirements of the secular-varia- 

 tion problem. 



With the view presented of the problem, some of the interest- 

 ing questions we may ask ourselves are: Will the orbit described 

 by the north end, say, of the needle, be a closed curve or approx- 

 imately so? That is, will the needle at the end of a certain period 

 assume the same direction that it had before, and again sweep 

 over the same curve in the same length of time? Or, will the 

 needle never return to a previous position, and thus never fulfil 

 a secular variation period? If we have such a thing as a true 

 period, is it the same all over the globe? If we have to deal with 

 different periods, as the discussions of declination observations 

 at various stations would seem to indicate, are these local or inde- 

 pendent, and thus belong to different systems of magnetic forces? 

 Or, do they but indicate different stages in the development of 

 the secular variation, whereby either the period itself is a fluotu- 

 ting one, or the orbit consists of several branches or loops ? If 

 the secular waves travel from east to west, traversing the whole 

 globe, then by making an instantaneous circuit of the earth in an 

 'easterly direction, shall we find the needle at every station farther 

 along in its secular orbit? Shall we find a continuously progres- 

 sive and consistent motion throughout our survey, thus correlating 

 the stations and referring the cause to a common origin ? If we 

 find this to ba but roughly so, then by selecting as a base station, 

 one where we have a long series of observations, we may with the 

 aid of the shorter series at other stations, by adopting a time-co- 

 efficient determined from a comparison of the curves, attempt to 

 answer some of the questions propounded without waiting until 

 centuries have given us a complete period ? Finally, what is the 

 law of force acting upon the needle to cause it to describe its 

 orbit ? 



To carry on a study of the secular variation to the best advan- 

 tage, it would be highly desirable that at all stations where we 

 have a tolerably long series of observations they be put in the best 

 shape possible by one familiar with the subject and the station. 

 It would then be an easy matter to establish secular variation 

 stations all over the globe, where future observations might be 

 made. This would mean simply the inauguration of a grand 

 scheme, the fruits of which mighi not be seen for centuries. 

 While such a gathering of material has already been made for 

 many stations, there is, however, abundant material left. 



The first station selected for discussion is London, where we 

 have the best series of observations of both elements. The de- 

 clinations date with Boroughs's in 1580. They can be represented 

 (within their probable error) by the following formula, derived 



2 See Bulletins de I'acadi^aile royale de sciences etc. de Bruxelles, 47nie an- 

 nee, 2<^^ aerie, T. slv. 



3 See U. S. Coast and Geodetic Survey Report for 18S5, App. No. 6, p. 273. 



