MARINE BIOLOGICAL LABORATORY. Received Accession No. Given by Place, ***flo book OP pamphlet is to be removed îpom tbe Iiab- ofatopy ujithout the permission of the Trustees. ^ ^ EH «• 9t3 THE JOURNAL OF THE COLLEGE OE SCIENCE, IMPERIAL UNIVERSITY OF TOKYO, Vol. XIV. :^ M ^ ^ :^ ^ fP ^T PUBLISHED BY THE UNIVERSITY. TOKYO, JAPAN. 1904. MEIJI XXXVII. Publishing Committee. Prof. K. IVlitSUkuri, Ph. D., RigakuhakusU, Director of the College (ex officio). Prof. J. Sakurai, LL D., RigakuhakusU. Prof. I. Ijima, Ph. D., RigakuhakusU. Prof. F. Ömoi'i, RigakuhakusU. Prof. S. Watasé, Ph. D-, RigakuhakusU. ^13 5 All communications relating to this Journal should be addressed to the Director of the College of Science. A MAGNETIC SÜEVBY OF c;.. JAPAN REDUCED TO THE EPOCH 1895.0 AND THE SEA LEVEL CARRIED OUT BY ORDER OF THE EARTHQUAKE INVESTIGATION COMMITTEE. REPORTED BY A. TANAKADATE niversity Tokyo. MARINE BIOLOGICAL LABORATORY. Received (2-t-^-— -^ // ^^ Accession No. »2- i>^ r / Given by Place, *^* flo book OP pamphlet is to be femoved f Pom tbe Iiab- oPQtopy tuithout the pepmission of the Trustées. Publishing Committee. ^^ Prof. K. IVlitSUkuri, Ph. D., Rigamakushi, Director of the College {ex officio). Prof. J. Sakurai, LL D., Rigakuhakushi. Prof. I. Ijima, Ph. D', Rigakuhakushi Prof. F. Omori, Rigakuhakushi. Prof. S. Watasé, Ph. D., Rigakuhakushi. 57 3 3 All communications relating to this Journal should Director of the CoUege of Science A MAGNETIC SUEVEY OF JAPAN REDUCED TO THE EPOCH 1895.0 AND THE SEA LEVEL CARRIED OUT liY ORDER OF THE EARTHQUAKE INVESTIGATION COMMITTEE. REPORTED BY A. TANAKADATE Proîcssor of Physics, Imperial University Tolcyo. Deflection Expt. PREFACE. The mngiietic survc}^ of Japan published in the present volume was conducted under the authority of the Earthquake Tnvestio-ation Committee durinor the four successive summers 1893-6. As will be seen from the complete list of observations, the work is the result of voluntary co-operations of the observers to whose skill and enthusiasm the success is due, and whatever credit there is in the survey it must be attributed to them all, the writer being merely in the position of reporter representing their different parties. The observers were : — H. Omort, Rigakuhalcusl, Prof, of Seismology, Imperial University Tokyo. S. Nakamura, Eifffckusi, Now Asst. Prof, of Physics, Imperial University Tokyo. K. MizüSiMA, Rigahusi, Now K. Miyamoto. H. IwAOKA, Rujahusi, Now Prof, of Mechanics, Higher Technical School of TokyH. H. KiMURA, Rlgahusi, Now Director of the International Latitude Observatory, Mizusawa. K. TuRCTA, Rigahuhahusly Now Prof, of Physics, Imperial University Tokyo. K. UzriE, Rigakusi, Now Director of the Middle School, Sendai. A. Imamura, Rlgahusi, Now Asf^t. Prof, of Seismology, Imj^erial University Tokyo. y. Kato, Rigakusi, N<~>W y. HoiMMA, VI PREFACE. T. Ta M ARU, Rigalcusi, Now Asst. Prof, of Physics, Imperial TTniversity Tokyo. T. To:\roDA, Rigahusi, Now Prof, of Pliysics Dai-iti Kütögakkö, Tokyo. D. Sltto, Rigahisi, Now Prof, of Physics, Dai-iti Kötügakko, Tokyo. S. Saxo, Rigalcusi, Now Prof, of Physics, College of Naval Engineering, Yokosuka. S. SlNZYo, Rigalcusi, Now Asst. Prof, of Physics, Imperial University, Kyoto. ;M. Hattort, Rigalcusi, Now Prof, of Pliysics, Naval College E lazima. A. Taxa K a date, The writir. The writer wishes specially to remember Prof. Dr. D. Kiknti, Baron, the President of the Earthquake Investigation Committee at the time, whose interest on the subject and whose cordial advice both official and scientific was of great encourage- ment to all of us. Thanks are also due to various public authori- ties and private persons who assisted the ol)servers in selecting the stations ; and to the three computers Messrs. T. Kariya, Rigalcusi, S. Kttsakahe, Rigalcusi and Y. Yasuda, graduate of the School of Physics in Tokyo, who performed that tedious work with care and patience. The spelling of Japanese names adopted in this volume is slightly different either from that in common use among English speaking people in this country, or from that of the Romazikwai system to which the writer is an opponent. The Goveriuiient Committee for the Improvement of the Language has lately brought forth a system which is a kind of compromise between the previous systems. At such a stage of orthographical reformation one might be excused to adhere to what he believes the best. PREFACE. VU The iippearance of tlio volume was mueli delayed by various eiicuuistances under wliieli the writer had to work. lu the course of the preparation he had to make two official trips to Europe and to take a half year's rest between those tw^o on ac- count of his health, beside having had to attend several unavoid- al)le committee works. But above all we regret the delay in lithographic printing which kept the work over three years. The publication however is quicker than otherwise it would have been through the kind assistance of his colleague Prof. H. Nagaoka who arranged the materials of the appendix and com- menced printing during his absence. A. Tanakadate. Physical Laboratory, Imperial University, Tokyo. March, 1904. Contents. Paok. § 1. Object of the Survey ] {; 2. Division of Work in Eacli Year 1> ^ ;>. Equipment and Procedure of Eacli I'arty 4 § 4. Instruments 7 'i Ô. Method of Observation 11 ^ 6. Diurnal Variation 21 § 7. Eeduction to 1895.0 22 ^ 8. Reduction to tlie tSea Level ;jO ^ 9. Isoniagnetics ;;ü 2 10. Mean Isoniagnetics ol ^ 11. Vertical Cin-rent 122 I 12. Vertical Variation of Magnetic Elements 120 ^ 13. Disturbance in the Vertical Variations of Magnetic Elements 141 § 14. Disturbing Magnetic Forces 17Ö Tables. Page. Table 1. Correction to be applied to tlie Estimated Fractions of Second when Simple Harmonic Motion is Observed by Eye and Ear ]MctIiod. ... 12 Taele II. Annual Variation of Declination 24-25 Table III. „ „ „ Dip 26-27 Table IV, „ „ „ Horizontal Intensity 28-29 Tabi,!'; V. Magnetic Elements Calculated fr< m X, Y, Z, expressed in Spherical Harmonics fur 1885.0 by Prof. Ad. Schmidt o2 Table VI. Magnetic Elements in the Neighbourhood of Japan calculated as (iuadratic Functions of Longitude and Latitude, from the Data given by Spherical Ilannonics for 1885.0 ?>o Table Vll. Declinations at 1895.0. at tiie Intersections of Entire Degrees of Longitude and Latitude o8-ö9 CONTENTS. Table VU J. Table IX. Table X. Table XI. Table XU. Table XIII. Table XIV. Table XV. Table XVI. Table XVII. Table XVIII. Taule XIX. Tabi,e XX. TABIiE XXI. Table XXII. Table XXIII. Table XXIV. Table XXV. Table XXVI. Table XXVII. Annual Variations of Doclinatioiis at tlie lutor.st'i'tions cif J'intirc I)egreos of Longitude and Latitude 4U-41 Dips at IS'JÔ.O at tlie Intersections of Entire Degrees of Longitude and Latitude 42-4u Horizontal Forces at 1895.0 at the Intersections of Entire Degrees of Longitude and Latitude 44-4.5 Total Forces in C.( I.S. at 1895.0 at the Intersections of Entire Degrees of Longitude and Latitude calculated from the Formula for Horizontal Force and Dip 46-47 X^orthward Forces (X) in C.G.S. at 1S95.0 at the Intersections of Entire Degrees of Longitude and Latitude calculated from the Fonuul;\3 for Horizontal Force and Declination 48-49 WestAvard Ft rces (Y) in ( IG.S. at 1895.0 at the Intersections of Entire Degrees of Longitude and Latitude calculated from the ForinuliX' for Horizontal Force and Declination 50-51 Upward Forces (Z) in C.G.S. at 1895.0 at the Intersections of Entire Degrees of Longituile and Latitude calculated from the Fornuihe for Horizontal Force and Dip 52-53 Observed and Calculated Values of Magnetic Elements (o, 0, H, and Ij Kfcduced to 1895.0 and Sea Level 54-85 Observed and Calculated Values of Magnetic Elements X, Y, Z, and Intensity and Direction of Disturbing Foi'ces 86-117 Alpiiabetical List of Stations. .. ...118-121 Vertical Current in Amperes per squr. kilom. at 1895.0 at the Intersections of Entire Degrees of Longitude and Latitude, Calcu- lated from the Formulre for Horizontal Force and Declination. ...124-125 Kectangular Components of Magnetic Force in Great Britain. ... 127 Data for tlie Calculation of Vertical Variations of Magnetic Ele- ments in Japan I'M A'crlical Variations of Magnetic Elements in Japan 1;j5 Data for the Calculation of Vertical Variations of Magnetic Ele- ments in Austria and Hungary lo6 Vertical Variations of Magnetic Elements in Austria and Hungary. 137 Data for the Calculation of Vertical Variation of Magnetic Ele- ments in Great Britain lo8 Vertical Variations of Magnetic Elements in Great Britain lo9 A'ertical Variations of Vertical Magnetic Force on a Sphere of unit Radius due to a Unit Pole 154 A'ertical Variation of Horizontal Magnetic Force on a Splierc of unit Kadius due to a Unit Pole 155 MAGNETIC SURVEY OF JAPAN FOR THE EPOCfT ISHÖ.O. xi Plates. Plates I — LIX. Plates LX— LXXXVII. Plate LXXXVIIT. Map 1. Plate LXXXIX. Map 2. Plate XC. Map 3. Plate XCI. Map 4. Plate XCI I. Map 5. Plate XCI 1 1. Map 6. Plate XCIV. Map 7. Plate XCV. Map 8. Plate XCVI. Map 9. Plate XCVIa. Map 9a. Plate XCVII. Map 10. Plate XCVTIF. ]\rap 11. Diurnal Curves of Déclinât ion. Topographs of Stations. Isog)nic Lines for 1895.0 and Distarbancss of Declination. Isocilnic Lines for 1895.0 and Disturbances of Dip. Lines of Equal Horiz mtal Intensity and Disturbances of Horizontal Intensity. Lines of Equal Total Intensity and Disturbances of Total Intensity. Lines of Equal North Component and Distnibances of Nortli Component. Lines of Equal West Component and Disturbances of West Component. Lines of Equal Vertical Component and Disturlianccs of Vertical Components. Lines of Equal Vertical Current for Japan. Lines of Equal Vertical Current for Austria and Hungary. , Lines of Equal Vertical Current for Great Britain. Magnetic Disturbing Forces in .Japan. ( ieological ^Map of .Japan. Xll Errata. Page. ?> Line 14 from botlon, put n comma after Sendai. „ 10 Line 9 ,, ,, for axil read axle. „ 2?> Line 2 from top, „ 1887..^! „ 1887.G1. „ 80 Line 10 „ bottom ^ „ H .. 12. „ b?) put. the minus sign to tlie first two numbers in the table. „ (129) Line ?, from top „ premissed „ premised. „ 147 Line 4 from bottom „ {;^^"^^ „ (^^^"^ ' " (below " (above ,, 151 Lines 7 from top and 9 from bottom ,, maximum „ minimum. „ 160 Line 10 from bottom „ Azimuth „ Azimuths. Plate XVIII. heading, read Jour. So. Col. Vol. XIV. Plate LX to LXXXVI. heading, for Vol. XIII „ Vol. XIV. Plate XCVII. Map. 10. Station No. ISS Honsyö, reduce the arrow line to 1.4 m..m. and turn the azimuth to 41° east of south as given in Table XVI P. lO.*]. Station Xo. 132 Abasiri, turn the arrow line in azimuth to 37° east of north as given in Table XVI P. 99. Errata. (N.B. Errata for the Appendix is given at its beginnmy.) Frontispiece for Declimometer read Declinorueter. Page vi Line 15 from bottom, „ was „ were. ,, x „ 8 „ top, ,, formula „ formnlœ. ,, xii first line, „ botton „ bottom. „ „ Line 6 from top, „ (129) „ 129. „ 3 „ 15 ,, bottom, change the comma to a semicolumn. „ „ last line, for boardering read bordering. „ 5 Line 3 from bottom, „ blancket ,, blanket. „ 9 „ 6 „ top, after Length, insert of magnet at 0°C. „ 15 „32 „ bottom, for transit read transits. ,, 31 „ 13 „ „ „ Those „ These. „ „ „1] „ „ before pantograph, insert a. read —6.^1. „ horizon. 33 Table VI, last column, for — 6.a 87 to 117, foot notes, „ horison 107 heading Altitude, insert * 111 „ for 1835.0 127 Line 2 from top, before by, insert 130 „ 7 ,, bottom, before ^" „ 135 end of the foot note, „ 140 Line 8 from top, after Gauss, „ 145 „ 4 „ bottom, to the end of the line insert (10) 149 „ 14 „ „ for assymptotic read asymptotic. iou „ 0 ,, „ ,, ,, ,, ,, 151 first line, change the full stop to a comma 152 Line 10 from top, for assymptotic read asymptotic. read 1895.0. efl^ectually. Z. a comma. 156 Fig. 7 157 dZ' 9Z "9Z" dz 9h'' 160 Line 2 from bottom, for laved dz laid. 164 )' 4 „ „ )> table )) Table. 165 )? 3 „ top, » then ,, them. 166 )) 11 » bottom, after The, insert numerical. 167 )) o ') top. for convension read convention. 168 )» 9 V J' » 9Y' OY' Is dz 173 )) 3 » bottom, ,, existance existence. » last line. )) attension attention. » )) )) 15 scaler scalar. 174 Line , 2 from top, » sitz Sitz. » 1) foot note. ÎJ Gauss Gesammelt „ Gauss, Gesanmielte. 175 » 6 from top. „ asimuth » azimuth. 176 )» 15 )) bottom. ,, occurrance „ occurrence. PL.XCVIa, heading. >J Emperical „ Empirical. A Magnetic Survey of Japan Reduced to 1895.0 and Sea Level. § 1. Object of the Survey. The object of the survey was to get a closer view of the distribution of magnetic force in the country than liitherto has been done. It is hoped that we may obtain in this way some insight into the tectonic character of the country which might throw light upon the distribution of earthquake disturbances with regard to time and space. The object w^as twofold, Hrst to obtain a general or normal, as it is sometimes called, distribution and second to get the extent and nature of local disturbances in special districts. With the first point in view a comparatively large number of stations were taken in places which were apparently free from distur- bances of any great magnitude ; and with the second point in view observations were made in volcanic regions or in places where violent geological changes are supposed to have taken place. How near we have come to realize those expectations is cleai-ly shown in the maps. It will be seen that we have done something toward the first, but for the second a much more extended series of observations are needed, although we believe that some of the prominent points are brought out by the present survey. A A. TANAKADATE. § 2. Division of Work in each Year. In 1893 the middle part of Honsyü was surveyed by two parties called for convenience the East Party and the West Party. The East Party consisted of H. Omori, S. Nakamura, K. Mizusima and H. Kimura and began its work on July 3rd. and ended on Oct. 23rd. It made observations at 44 stations covering the district between the island of Sado on the uortli and the peninsula of Idu on the south, and from the Lake Suwa to the plane of Sumidagawa across the other directions. It took several observations on the active volcano Asama. The West Party consisted of A. Tanakadate, K. Turuta, H. Iwaoka, and K. Üziie beside T. Noda who joined the Party for half of the time. It began its work on July 1st. and ended on Oct. 27th. and made observations at 47 stations in the district extending between the peninsula of Noto on the north to the harbour of Toba on the south, and from the shore of the Lake Biwa to the eastern foot of Huziyama on which several observa- tions were taken. This party had the mishap of breaking the spider line suspension of the magnetometer at the first station after Tokyo, and on repairing an unforeseen blunder was committed by using too thick a fibre, the erroneous effect of which was discovered at the station Gihu after making observations at 22 stations. This affected the value of the horizontal intensity but a little, its effect upon that of the declination was however too great to be allowed ; hence A. Tanakadate left the rest of the party at Turuga and made re-determinations of that magnetic element at those stations except a few on the top of Huziyama. MAGNETIC SURVEY OF JAPAX FOR THE EPOCH 1895.0. 3 In 1894 the Island of Hokkaido was surveyed by two par- ties called the Korth Party and the South Party. The North Party consisted of A. Tanakadate, K. Mizusima and IT. Kimura; it began its work on June 2Gth. and ended on Oct. 15th. and made observations at 38 stations covering the whole district lying to the north of Yûbari range and Mororan Bay^ While makinfij observations at Asahi2;awa the 12th. station of the year, Iv. ]\Iizusima got a sting of an insect on his eye which became so serious that medical treatment was necessary, and H. Kimura was called to take his place, who again after working on 13 stations was obliged to leave the Party at Nogami on account of fever, so that the remaining stations were ob- served by Tanakadate alone. The South Party consisted of S. Nakamura and A. Imamura and began its work on June 26th. and ended the work on Oct. 28th., it made observations at 28 stations including Tokyo and Sendai on the southern half of the island approaching the dis- trict of the North Party at Nemuro and Setana. In 1895 the northern part of HonsyQ was surveyed by two parties called the North Party and the South Party. The North Party consisted of A. Tanakadate, S. Sinzyö and Y. Kato, and began its work on June 23rd. and ended on Sept. 13th. and made observations at 37 stations covering the whole district lying to the north of Sendai. This Party had the assistance of Z. Tatihara near the end of the work. The South Party consisted of S. Nakamura, A. Imamura, T. Tamaru and D. Sutö, and began its work on June 23rd. and ended on Sept. 4th.; it made observations at 32 stations covering the district lying to the south of Sakata to the penin- sula of Awa-Kazusa boardering on the west on the valley of 4 A. TANAKADATE. Sinanogawa. This party made observations at a few stations of the East Party of 1893. In 1896 the sonthwest of Honsyû, Sikoku and Kyûsyû was surveyed by three parties, called the Kinki Party, the Seto Sea Party and the South- West Party. The Kinki Party consisted of S. Nakamura, Y. Katö and T. Tomoda, and began its work on June 30th. and ended on Sept. 6th.; it made observations at 28 stations covering the dis- trict lying to the west of the Sea of Ise up to Okayama Bay making a point on the Island of Awadi. It took observations at a few western stations of the West Party of 1893. The Seto Sea Party consisted of A. Tanakadate, D. Sutö and S. Sano, and began its work on June 26th. and ended on Oct. 7th.; it made observations at 43 stations covering the dis- trict lying to the north and south of the Seto Sea on the west side of Okayama Bay, and three stations on the northeast of Kyûsyû. The South-West Party consisted of A. Imamura, S. Sinzyö and M. Hattori, and began its work on June 28th. and ended on Sept. 7th.; it made observations at 30 stations covering the whole of Kyûsyû except the three stations above mentioned. In counting the number of stations, the base station Tokyo and some of the repeated observations at the same station in different years are included ; while those places where only dip and vibration experiments were made are excluded. § 3. Equipments and Procedure of each Party. Each party was equipped with a set of magnetometers, a chronometer, a tent, a folding soft adapted for bed, a battery of MAGNETIC SUKVEY OF JAPAN FOR THE EPOCH 1895.0. 5 dry cells, small electric lamps, a box of necessary tools and materials, besides the "Berliner Jahrbuch," a logarithm table and note books. The magnetometer is described in the next section: All the chronometers used were siderial, made by Negus, New York. The tent was specially designed for the purpose, it is round 3.5 meters in diameter pitched with a center pole of 2.7 meters length. It is made in two parts, a conical top and a cylindrical wall, each of which can be folded back partly or wholly to accommodate various circumstances. It has a mosquito net fit- ting inside closely throughout. The top can be opened for astronomical observations and turned round after the fashion of an equatorial dome. Observations were often made with the net on, this caused diffraction phenomena producing four images with tails round the central spot, corresponding to square meshes of the net. The effect is however of no importance for the kind of work we are concerned with. On hot days the wall was removed giving the tent an appearance of a large umbrella with hanging curtains. This defence against insects proved also to be a useful guard for the instruments against wind and dust. The tripod for the magnetometer was set on the east side and that for the dip circle on the west, and the sofk on the north ; a small shelf was rigged to the center pole for laying notes and small articles. The magnetometer, dip circle and chronometer were carried by the observers themselves in travelling by rail or carriage, in crossing over mountains they were usually carried by coolies or sometimes on horseback ; the chronometer was well corked round the gimbals and the box thickly wrapped in blancket which secured it both against mechanical jars and abrupt changes of temperature. 6 A. TANAKADATE. The selection of station was done by what was called the forerunner " Senpatu-in '' who came to the place a day or half before the rest of the party and made necessary examination and arrangements. Stations were taken with the usual precau- tion against disturbances from buildings, railways, iron bridges, electric plants, factories &c.; care was also taken with regard to the permanency of its surroundings in order that observations may be repeated in future at the same place, although there must be allowed a large margin of uncertainty in this respect. PI. LX to PI. LXXXVII are topographs of stations. The objects to be represented for the identification of places are so various that the uniformity of scale and orientation could not be followed ; in most cases they are sketches taken by the observers and are to be looked upon as mere substitutes for verbal description. No member of the party was specialized to take any par- ticular kind of work, on the contrary each had to do all the operations by regular turn including even the business part of acting as the forerunner above spoken of. This was insisted on, not on account of equal sharing of labour but for the object of eliminating personal errors of observations and peculiarities of manipulation which were likely to be thus discovered. This gave also the party the power of continuing its prescribed work even if it be reduced to one person through accidental failure of the rest, which unfortunately happened more than once during the survey. In the last two years of the survey, besides making regular sets of observations in the tent, observations of dip and horizontal intensity by vibration only were made at two or three points in the neighbourhood, under the protection of a parasol from MAGNETIC SURVEY OF JAPAN FOK THE EPOCH 1895.0. 7 which iron was replaced. The result verified to a certain extent the selection of the station. Local disturbances in an apparent- ly smooth plane were sometimes surprising. Those points are not numbered in the list but are given as " Syuttyo "; Nos. 54 to 61 in the first year are of this category, and they would have been so named had they not been observed with the express view of finding the effect of Huzi. § 4. Instruments. There are four sets of magnetometers belonging to the Earth- quake Investigation Committee, three of which were used in the survey. Their construction is the same in principle as that adopted in the magnetometer used by the South Party of the magnetic survey of 1887, and fully described in Vol. II p. 178 and Vol. V p. 163 of this journal. The plate in the front page is the photograph of No. 1 instrument. The theodolites were ordered from Troughton and Simms of London for the special purpose. The graduated diameter of the azimuth circle is 18 cm. and that of the altitude circle 17.5 cm., both are divided to every 10' and are read with two verniers to 10". The telescope is of 4.8 cm. clear aperture and 36 cm. focal length and has five transit wires of about 10*^ equatorial interval. The modifications now introduced in the part of magneto- meter are of minor importance being simply for the convenience of manipulation, they are : — 1. The magnetometer which is now put in a metal tube to guard against electrostatic effect of glass tube. 2. Magnetometer stand which is in the form of a tube standing upon three legs and can be fixed either to the base 8 A. TANAKADATE. plate of tlie theodolite for declination observation, or to the base of Y's for deflection experiments, by working the differential screw at the center. (See pi. in front page.) 3. Use of autocolli mating telescopes, which makes the in- strument more compact. 4. Cylindrical form of vibrating magnet which facilitates the use of transporter. 5. The transporter with which the magnet can be carried from one position to another on deflection bar or reversed in direction with great ease, without the danger of imparting heat from the hand of the observer. Fio:. 1. It may be remarked here that Mr. Ch. Chree's objection to the Kew pattern of deflection bar was looked into in 1887 already, though not expressly stated. From the photograph in the front page, it will be seen that the correction arising from the flexure of the bar is very small in our design. 6. The use of the dip circle box for vibration box : for this purpose two Y's were provided on the base plate of the box. When the bar magnet was laid on those Y's its axis was horizontal and it was so adjusted in azimuth that its direction, MAGNETIC SÜEVF.Y OF JAPAN FOR THE EPOCH 189Ô.0. 9 as observed b}^ the reflected line in the focus of the telescope from its polished end, remained unchanged, when it was lifted up slowly by screwing up the suspension fibre. The instrumental constants are as follows : — No. 1 No. 2 No. 3 Length in cm. 6.9911 6.9907 6.9461 Diameter ,, „ 0.7912 0.7982 0.8060 (mean) Weight ,, gr. 26.6640 27.1638 27.4545 Moment of inertia, I 109.643 112.150 111.505 (gr. cin-.) Distances of center ( r, of magnet from } magnetometer in cm. ( *- 30.0130 23.0023 29.9945 22.9941 30.0363 22.9747 log i/cizvT) 2:i8183 2.17692 2.17817 log Y^ 7.38655 7.38521 7.38823 log r,'^ 6.80886 6.80808 6.80625 1... l-2/Vr,r,(r, + r,) 3.12872 3.12878 3.12561 fi = 3.S for all the magnets, fonnd hy magnetometric metliod. Those bar magnets were selected from ten of similar ones. The moment of inertia is calculated in two ways, once from the linear dimensions and weight, and again by comparing it with that of a brass cylinder belonging to Kew magnetometer No. 64 hj vibration method : the latter gave always slightly greater values than the former which may be due to heterogeneity in its density; but as vibration method is not entirely free from uncertainty, inasmuch as the time of vibration is usually affected by small fluctuation in the value of the horizontal in- tensity during the experiment, the mean of those two values is adopted in reducing the observations. There are three dip circles belonging to the same committee 10 A. TANAKADATE. made by Ciisella, these are Nos. ÖG13, 5G14, and 0015; after 1894 tliey are nuni leered as 1, 2, 3, respectively and are put together witli the magnetometers of corresponding numl)ers. In 1893 one dip circle (Casella No. 4365) was borrowed from the Hydrographie Bureau for the East Party and another (Dover No. 88) from the Science College for the West Party. For reversing the magnetisation of needles a pair of coils each wound with insulated wires of three difterent diameters ; the thinnest being put innermost, was made for each set of in- struments. They were put in a closely fitting box which acted also as sliding guide in introducing the needle safely into the narrow cores. The usual bar magnets were only carried to provide for the case of the failure of dry cells. The declinometers were electromagnetic, the same as those used in the survey of 1887, the only difference being in tlie construction of the mirror magnetometer already described. Simultaneous ol)servations were made with those instruments at various times as is seen in the Complete List of Observa- tions, and differences were found. They arise from the errors in the determinations of the constants, from the errors of gradua- tion and the eccentricity of the circles, from the deviation from circular form in the axil of dip needle besides the accidental errors of observations. The difference will depend upon the local values of magnetic elements and different sets of observers to certain extent, hence we have not applied instrumental corrections in any of the results, the constants of the magne- tometers were however determined at various intervals during the survey. The distribution of these instruments among the several parties were as follows : — MAGNETIC ÖUKVEY OF JAPAN FOK THE EPOCH 1895.0. 11 18U3 1894 1895 1896 Magnetometer. Dip Circle JEast Party No. 2* Casella No. 4365 West Party No. o O Dover No. 88 1 North Party No. 1 Casella No. 5613 ISoiitli Party No. O No. 5615 1 North Party No. 1 No. 5613 ISouth Party No. 3 No. 5615 Kmki Party No. 1 No. 5613 Seto Sea Party No. 2 No. 5614 South-West Part^ i No. O No. 5615 ^ 5. Method of Observation. The Vibration Experiment \y;is always made [)efore the de- llection experiment in determiniDg the horizontal intensity. This was generally done by two men, an observer gave signal of the transit of the reflected line in the ol)serving telescope by making a tap with a small piece of wood, and a recorder looking at tlie chronometer noted dow^i the time estimated to nearest tenth of a second ; 15 successive transits in the same direction were observed at the beginning and end of 50 complete vibrations, the chrono- meter being placed at 11 meters distance from the magnetometer. When it was performed by a single person the eye and ear method as in the case of star transit was employed ; this I'ecpiires the period of magnet to be greater than four seconds. A correction on account of the non-uniformity of the visible jnotion is applied which is easily found to be * In 1893 the bar magnet No. 1 was used with tlie nitignetunieter No. 2 and the reduction is carried accordingly. 12 A. TANAKADATE. 2- tix sin '2tc]z — n cos •2;r/r + (1 — n)lib wlieru ?i is the estimated fraction of a «ecoiul and " tlie [)L'riod of vibration of the magnet. Tal)le I is constructed for the purpose. TABLE I. Ourrections to be Applied to the Estimated Fractions of Hecond when Sirajjle Harmonic Motion is Observed by Eve and Ear Method. 1)1 \^ Period Fi-actions \ of second \^ 5** (>^ ;« 8« O .ooo .000 .000 .000 .000 O'.I -.030 — .019 -.013 —.010 — .007 o^2 -.044 — .027 -.018 -.014 — .010 o^3 — .042 -.025 — .017 —.012 — .009 0^4 — .026 -.013 — .010 — .007 — .005 o^5 .000 .000 .000 .000 .000 o\6 + .026 + .013 + .010 + .007 + .005 o^7 ■f .042 + .025 + .017 + .012 + .009 o^8 + .044 + .027 + .018 + .014 + .010 o^9 + .030 + .019 + ■013 -L.OIO + .007 r.o .000 .000 .000 .GOO .000 The magnet is suspended with two loops of silk tibre as in Fig. 2 and is free from any mechanical stress except the pressure due to its own weight. The looj^s weigh about h milligram and rm Natural Hizc. MAGNETIC SURVEY OF JAPAN FOR THE EPOCH 1895.0. lo their lowest ends are nearly 2 cm. apart, so that its moment of inertia about the vertical axis is less than 0.0003 gr. cm.'- and is neglected in the calculation. The inclination of the magnet is adjusted by movins; the small tie E in Fig. 2 within fraction of a minute. The magnet is subject to a slight motion in the vertical plane caused by accidental distur ba n ces of the air or ground tremors. This effect as well as that of the inclination upon the proper period of vibra- tion was specially studied l)y making observations with large amounts of those errors ])ur]iosely given, as follows : — Kogota July 1st. 1895. Local Time Temperature y^brntion 11" 11" 11" Observer H. !~>inzy(). Recorder A. Tanakada'J'e. Remark. 24'" A.M. 20^6 C. 5\8810 normal p.)sitiou 41'" „ 20 .9 5 .8785 nortli end down 30' -,,,„ ^^,. r- ~ Qi-Qr^ (with motion in the vertical '^^ " ^^^-^ O.b/öü Ipiane, amplitude 30' to l.y 1" 06™ P.M. 2r.o c. 5\8796 normal position 1" 15'" „ 21 .4 5 .8770 north end up 27' 1" 47'" „ 21 .3 5 .8797 „ ,, down 30' 2" ?àT P.M. Oh ooiii 21°.5 C. 21 .2 5*.8851 normal position " QQ~ (1 /* Dir. (I) 9" 49' 30" 189° 49' 30- (4) 9° 50' 0'' 189° 49' 50" 1-tev. (8) 357 53 0 177 52 50 (5) 357 57 30 177 57 40 Difi: 1 1 56 30 II 56 40 Î II 52 30 II 52 10 Mean 11° 56' : S'' . 11° 5° 54' 57' 27''. I v. 8 11° 52' 20'^ r„ = - -.-.= Dir. (ij 17° 21' OS'' 197° 20' 50'/ (3) 17° 21' 50" 197° 22^ 05" Rev. (7) 350 16 30 170 16 50 (6) 350 30 5 170 30 20 Diff. 27 4 35 27 4 0 26 51 45 26 51 45 Mean 27° 4' 1 7". 5 26° 58' I ^° 2q' 26° 51' 45' h oo'^6 Temperature Ended 16 15.2 Began 15 46-2 I nitial 27°.o c Tab. Vr. L. r,^. 7 ■ 3 S '5 5 5 Mean 16 co.7 a Log. Tab. L. sin ? , 2 1.01589 ,A T - 40.5 15''' 20.2 b 26°. 8 c (i)+(2) L. r j= sin 5, 3 6.40244 Mean 26°.g c Tab. VI. L. r./ 4 6.80886 C'orrn. 0 Log. Tab. L. sin (f.-. 5 T . 3 6 7 6 6 26°.9 c (4)-t-(5' L. r/ sin a,. 6 6.17652 (3)-f6) 1 *'inal 26°.5 c Log. Tab. Vr/ sin 0., / 7 7.8 34 02 0.22592 Tab. VI. J I — 2[jL/r,r„(r,+r„) 8 3. I2S72 2(r,--^-r/) 1) 26^4 c Tab. VII. L. (i+fU) 9 0.00067 Mean 26^45 e (6)+. ..10) L. ^r/Ir 10 3 • • 3 0 0 ^ Corrn. 0 L. \/3J/H II 1.56997 26°.45 e L. vVTmH 12 " . 9 4 5 s 0 * (M) 26 .68 (II)-(I2) L. M ^3 •4 2.62417 M = 420.8:j fv-t,l 15 ('3)-(io) L. H T. 48424 II = 0.30496 i.1 -t,,)iOLH cnrrn. = 4 H = 0.30500 18 A. TANAKADATE. SPECIMEN PAGE OF OBSERVATIONS Inslniment No. 3. Date Orl. 6fh. 1894. Time ^v E Mean Zero Keailing and Mean h m 0 / // Ü / // 0 / // 0 / // 18 42.8 œ a I 3« 40 35 55 5 42 14 -M b 181 39 20 36 30 49-2 ^ m 39 0 36 12.5 I 37 36.3 Ä (( 3 S 10 35 0 ^ h 38 55 35 50 46.0 r^ )ii 3S 32-5 35 25 36 5S.8 1 37 17.6 20 1.8 œ II I 3S 0 35 15 11.6 ^ S S b 181 38 50 36 0 37 1.2 m 38 25 35 37-5 ^ (1 37 50 35 20 b 3S 20 36 10 36 55-0 I 36 58. 1 6.7 m 38 5 35 45 21 14,0 œ a I 34 30 38 0 -^ b 181 35 25 38 40 19.8 s m 34 57.5 38 20 3f> 3S.8 ï^ a 35 10 38 0 f", h 35 50 38 50 36 57-5 I 36 48. 2 16.9 m 35 30 38 25 I 19. S aj (( I 38 50 3>' 15 rM b 181 39 50 37 10 27.0 ^ m II 39 20 36 42.5 38 1.2 ^ 38 50 35 45 ■^ h 39 35 36 40 23.4 r-, m 39 12.5 36 12.5 37 42.5 I 37 51-9 X II -^ b m a -M b m MAGNETIC SURVEY OE JAPAN EOR THE EPOCH 189;").0. 19 FOR FINDING THE DECLINATION. Place Nemvro. 5 Observei- Recorder Remark o / // 4° 4' 56" Nakaimua Tinaniiira 4° s' 16'^ ); Nakaiiiura 4° 5' 26" )) )j 4° 4' 22'' " )( Oct. /til. 20 A. TANAKADATE. SPECIMEN PAGE OF OBSERVATIONS FOR FINDING THE DIP Plane Tniaiti. InMmmenl No. 2. Needle No. 1. Began 3 3.2 p.m. Bate July :\lsl. lS9(i. Observer Sano. Recorder Sut5. Ended 3 3S.3 p.m. Axis of needk' Circle Adjusted to upper end Adjusted to lower end Mean Direct S 23° 55' 23° 38' 23° 26^.25 N 22° 56' 23° 16' Mean 23° 25^.5 23° 2f Heversed N 23° 26' 23° 39' 23° 2S'.75 S 23° 32' 23° 18' Mean 23° 29' 23° 28'. 5 Azimuth ,' Adjust- ed to a \ h (vernier) (vernier) j\Iean a (vernier) b (vernier) ^lean 0 a» 0 ■r. E up 49° 39' ° 40' 49° 42^5 49° 47' ° 47/ 49° 47'.o down 45' 46' 47" 47' Mean 42' 43' 47' 47' W np 52' 52' 49'5 50° 24/ 24' 50° 24'.0 down 47' 47' 24' 24' Mean 49'.5 49'.5 24' 24' -0 I W up 49' 50' 50:75 05' 06' 50° 03^.0 down 52' ! 52' 00' 01' Mean 50'. 5 51^.0 02'. 3 03'. 5 E up 35' 1 36' 34^75 02' 03' 50° 05'.5 down 33' 35' 08' 09' Mean 34' 35'-5 os'.o oö'.o Me an of Means 49° 44^4 INIean 0 f Means 50° 04'. 9 Dip 49° 54'.6 MAGNETIC SURVEY OF JAPAN FOR THE EPOCH 1895.0. 21 early in the morning, or at the noon the 8un's transit, except when prevented by unfavourable weather, for which cases the rate and error were interpolated from the previous and succeed- ing observations. As the state of the weather can not usually be relied upon, the first chance of making astronomical observations was always taken advantage of, l^e it the sun or the stars either in altitude or meridian passage. The comparatively large telescope was designed for this reason, to enable us to observe large stars through mists or thin clouds ; a still larger aperture, though sacrificing a little definition, will be recommendable in future. § 6. Diurnal Variation. The corrections for diurnal variations are not applied, being eliminated to a large extent by taking the mean of three or more sets of observations of all the magnetic elements in each of principal stations (see Complete List of Observations in the Appendix). A set of experiment for the determination of the horizontal in- tensity and the dip was made in the morning about 8 or 9 a.m., another near the middle of the day about 1 or 2 p.m. and the last in the evening about 6, and often a set Wcis made at night after finishing the astronomical work, when that was done under favourable circumstances. Strict times of observations could not be followed on account of the conditions of travelling and also because of the astronomical observations, which had to )je taken at ^vhatever time that was available. Declination was observed at as many intervals as ])ossibh', so as to enable us to draw the diurnal curves (see PI. 1. to PL LIX.) at each principal station. The mean value is obtained 22 A. TANAKADATE. by ]:)lainmetric method, and is indicated by a dotted line in the phite, where only a part of the curve is obtained the mean is inferred from those of tlie neighbouring curves. The diurnal curve was also useful in warning the observers of magnetic storms, during which the regular observations had to be sustained. § 7. Reduction to the Epoch 1895.0. In order to reduce the observed values to a common epoch, we require to know the secular variation of each magnetic element. It was hoped by taking observations at the stations of the pre- vious survey of 1887 this might be found at each place. On carrying out the work, however, it was found that observations in most of the old stations were impracticable on account of changes that have since taken place in their surroundings. Al- though many of the names in the list of observations are the same, there are only 7 places where regular observations were made at the identical spot ; the values of dip and horizontal intensity given in tlie list under the heading " Station 1887 " were nnxde again now for the sake of reference even though the surroundings had somewhat changed. Under these circumstances it was considered not expedient to derive the annual variation in the way first thought of. The method used is to find mean secular variations by com})aring the empirical expressions of magnetic elements in terms of longitude and latitude, which were already worked out by Prof. Knott, with those of the present treated in similar manner, su})posing those two sets of values to represent the magnetic state of the country at the epochs corresponding to the means of MAGNETIC SURVEY OF JAPAN FOR THE EPOCH 189Ö.0. 23 the times of observations in the two surveys : these fell respec- tively 1887.51 and 1895.12 during whicli interval the variation is assumed to have ])een uniform ; thus : — d=:)° o.i'(;4-o.'2S6'Jç'-o:i44j;.-o:ooo294(j;.)- at 1895.12 0=4° 54.'4+0:241J^-0.'l33J;-0.'000231(J/)- „ 1887.61 J.;= li:2 + 0:04.3J(P-0:011J>i-0:OOOOG3(j;0' for 7..3I year«. and -'^-1:49 + 0:OO.j!J:JJ^--0:û314GJ/-0:0000084(J;0' per annum where J^" = (^— 37°)', J/^. =r(/ — 138°/ * expressed in minutes similarly ^ = .30° 47:4+i:0G8J^-0:0792j;. at 1895.12 H=ho° .54:9 + 1. 'i4(;j^- on .5.5GJ;. ,, iss7.gi Jd=^ - 7:.3-0.'Ü78Jv^ + 0:07G4J/. for 7..'31 years. ^^z= -.l.'00-0:0104Jc? + 0.'0l02J/ per annum 11=29317- G'i2_f^-l!48j;. at 1895.12 H = 29247'-G.'l7J^-l'.17j;. „ 18S7.G1 JH= 7d + 0.'05Jy^-0'.31j;> for 7.51 years. ^^= 9'.33 + 0'.00G7J^-0!041J;. per annum. The vahies for 1895.12 were derived from the results of observations at 288 stations which w^re seemingly free from ex- travagant local disturbances by the method of least squares, a process somewhat superfluous but useful in training the com- puters for further work. Tables II, III, IV, give these annual variations for each degree of longitude and latitude throughout the country and were used in reducing the values to the epoch 1895.0. * The origin is taken at round number of degrees instead of the mean value for facilitating the use of the formuhe, tlie slight increase of probable errors in the comiuted values thus caused is quite insignificant. 24 A. TANAKADATE. ANNUAL VARIATION / c 1-29° 130° 131° 132° 133° 134° 135° 136° 137° 46° 4.V 41° ! 42^ 41° - - 40° 3Î)^- 3S° 1 + 1 .'90 37° 36° 35° 34° + i.'54 + 1-55 + 0:58 + o.'82 + 1 '0 1 + 1-13 + I. '19 + I .'20 - o.'o8 + o.'23 + o.'47 + 0:65 + 0:78 + 0:84 + 0:85 -o.'79 -o.'43 — 0.' I 2 + 0.'l2 + o.'30 + 0.43 + 049 + 0:49 33° -1-57 -i.'iS -0:78 -0.48 -0:23 — 0.05 + o.'oS 4-o.'i4 i 32° -I. '50 -I -1 3 -0:83 -0:58 1 31° -1^85 - 1 48 -i.'i8 l'>9° 130° 131° 132° 133° 134° 135° 136° 137° MAGNETIC SURVEY OF JAPAN FOR THE EPOCH 1895.0. 25 II. OF DECLINATION. {See Table VIII.) 13S° 139° 140° 141° 142° 143° 144° 145° 146° 1 / + 3-82 46° 1 45° + 3:76 + 346 1 + 3-10 1 + 341 ' +3-11 + 2.75 -^2:y, + 1-85 + 1:31 44° + 3-30 + 3:06 +2:76 + 2.40 + 1 .'98 + I .'50 + o.'96 43° 1 1 1 + 2.9:; +2:71 +2.41 1 + 2.05 42° 41° + 2. '60 +2:36 + 2. '06 + 1:71 1 + 242 + 2.'25 +2.0 1 40° + 2.07 + I .'90 4- 1 '-66 + I .'36 39° + I .'84 + 172 + I. '54 +1-31 + i-'oi i 38° 37° 36° + 1 49 + i'37 + i.'i9 +0.95 +o.'66 4- I. '[4 + I .'02 + o.'84 +o.'6i + o.'79 + o.'67 + o.'49 + o.'2 5 1 35° 34° + 044 + 0:32 + o.'i4 . i 33° 32° • 31° 18S° 139° M()° 141° 1 UV 1 i 143° 144° 145= 14()^ m A. ÏANAKADATE. TABLE ANNUAL VARIA- 129° 130° 131° 132° ! 133° 134° 135° 136° 137° 46° 45° 44° 43° * 42° 41° 40° 39° 38° -2:24 37° — 2. '2 2 -1:61 36° -4-05 -3-44 -2:82 — 2.'2I -1Î60 -0:99 35° -4-03 h" \ 1 — 3^42 — 2.'8l — 2.'20 -1-59 -0:98 -0:36 34° — 4'02 -3-41 -2:80 -2:19 -1:58 — o.'çô -0:35 + 0:26 33° — 4'oi -3-40 -2-79 -2:18 -1:56 1 J -o.'95 I -o.'34 4-o.'27 32° -2:78 — 2.' 16 -1:54 -i'55 r , ^ -0.94 31° -2^15 r -o.'93 129° 130° 131° 132° 133° 134° 135° 136° 137° MAGNETIC SURVEY OF JAPAN FOE THE EPOCH 1895.0. 27 III. TION OF DIP. 138° 13î)° 140° 141° 142° 143° 144° 145° 146° -4:17 ' 4G° ! — 4'i6 -3'54 -2 .'93 45° 44° -3-53 — 2^92 -2:31 -if70 -1:08 -o.'47 -3-52 — 2 .'9 1 -2. '30 - 1 .'68 — I .'07 -0:46 + o.'i5 43° — 2. '90 -2:28 -1:67 -1:06 42° -2:27 - I .'66 - I .'05 41° — 2^26 -1:65 — I .'04 — 0.42 40° -1:64 — I .'02 — o.'4i + 0.'2I + .'020 39° 38° -1:62 — I .'0 1 — —J — 0.40 + o.'82 — I .'00 -0.39 + 0.'22 + 0^84 37° ; -0:38 +0:24 + o.'85 + 1:46 3()° + 0.'2 5 + 0:86 + I -47 + 2:08 35° + 0:87 + 1:48 + 2'lO 34° 33° 32° , 3P 138° 139° 140° 141° 142° 143° 144° 145° 140° ,.F •28 A. TANAKADATE. TABLE ANNUAL VARIATION OF 129° 130° 131° 132° 133° 134° 1 135° 13B° 137° 40° 45° 44° 43° 42° 41° 40° 39° 38° T + 12.2 37° + H-3 T + 11. 8 30° 35° T + 21.2 + i8!8 + 16.Z T + 13.8 T + II. 4 T + 25.7 T + 23.3 ] . + 20.8 T + 18.4 + 15-9 + 134 T 1 + I I.O 34° 4- 27.8 + 25-3 Ï + 22.9 + 20.4 + 1 s'.o + i5'.5 + 13.0 + 10.6 33° 32° T + 29.9 + 27U T + 24.9 T + 22.5 T + 20.0 + 17^6 + i5.'i + 12.6 Ï + 27.0 T + 24.5 T + 22.1 + 19-6 31° T + 26.6 T + 24.1 T + 21.7 129° 130° 131° 132° 133° 134° 135° 130° i 137° MAGNETIC SURVEY OF JAPAX FOR THE EPOCH 1895.0. 29 IV. HORIZOiNTAL INTENSITY. 138° 139° U()° Ul° 142° 143° 144° 145° 146° + 3^1 46° 45° + 5-2 + 2.7 Y + 0.2 Y + 4-Ö I T + 2.3 Y — 0.2 Y -2.6 Y -5-1 1 Y -7-5 44° T + 6.8 + + 3 + 1.9 -o'6 -3-0 : -5.5 -7-9 43° T + 6.4 Y + 4-0 Y + 1.5 Y — I.O 42° + 6!o Y + 3.6 Y + 1.1 41° T + 8.1 T + 5.6 + 5-2 + 3-2 + 07 40° Y + 2.7 + 0.3 39° T + 9-7 Y + 7-1 Y + 4.8 Y + 4-4 Y + 2.3 Y — 0. 1 38° + 9-3 + 8.9 T + 6.9 Y + 1.9 37° + 6:5 + 4'.o + 1-5 36° H-S.'s + 6.1 \ Y 1 + 3.6 Y + I.I 35° + 8.'i + 57 + 3-2 • 34° • 33° 32° 31° 138° 139° 140° Ul° 142° 143° 144° 145° 14(>° 30 A. TANAKADATE. This method gives only the average secular variations, the results are therefore partly over-corrected and partly under- corrected especially in regions under the process of tectonic change, some of \Yhich had already drawn our attention.* To minimize such effects the nearest round number of years to the mean time of all the observations is taken as the epoch to which all the observations are reduced, the amount of maximum correction l)einir about one and a half year either wav. It is to be remembered in this respect that three destructive earthquakes have occurred between the previous survey and the end of the present : the strongest in 1891 in the district of Mino-Owari and two less severe, one in Sakata in the winter of 1893 and another in Tokyo in the summer of 1896. § 8. Reduction to the Sea Level. To reduce all tlie observations to the sea level, the vertical variations of the magnetic elements were derived in the way dis- cussed in § 11 below, using the first approximation of mean isomagnetics used in deducing annual variations. The corrections are quite sensible in some of stations which are two or three kilometers high and affect materially the amount of disturbing forces in such altitudes. § 9. Isomagnetics. The reduced values of magnetic elements were ^^ut on maps, one for each element, and isomagnetics were drawn l)y the tent- ative method of interpolation, taking care to give slight allow- ances with respect to second differences. In some plac-es it was * The Disturbances of Isomagnetics atteudiiij? the Mino-Owari Eartliquake of ISUl, A. Tanakadate and H. Nagaoka, Journal of Science College, Vol. V. part II. MAGNETIC SUßVEi" OF JAPAN FOR THE EPOCH 189Ô.0. 31 difficult to decide wliicli course the curves will take, and recourse had to be made to the comiiion sense estimate or guess ivork. To draw those curves with accuracy " over even the smoothest hillside " to use Lord Kelvin's words with regard to the dis- tribution of atmospheric electricity, " would infiniteh' transcend human mathematical power." Mr. S. Nakamura and the writer starting separately on different sheets obtained curves agreeing in general appearance, but in particular details they differed widely in some places, the curves in INIaps 1, 2, and 3 drawn on transparent sheets, are a compromise made Ijy the writer. Actual values at each station, corresponding to the nearest mark 0 on the maps, are given along with the curves, so that they can be reconstructed by any one to suit his own view. The controversy which has risen in this respect in the result of previous surveys is thus avoided. Those curves were prepared on a larger scale of linear dimension five times those given in this volume and were reduced by pantograph. § 10. Mean Isomagnetics. The mean isomagnetics are re2)resented by empirical fornud^e expressing magnetic elements in terms of longitude and latitude in the usual way. Number of terms to be taken in such expressions depends upon the character of distribution of these elements in the country. By way of trial these elements were calculated for 12 points in Japan from the table of magnetic elements for the globe corresponding to 1885.0 as given by Prof. Ad. Schmidt," in which the expansion is carried to seventh harmonics. Table V shows the distribution of these points. . * Aus dem Archiv der Deutscheu Seewarte XXI Jahrgang 1898 No. 2, p. til. 'TO OL A. TANAKADATE. TABLE V. Magnetic Elements Calculated fronj X, Y, Z, Expressed in Spherical Harmonics for 1885.0 by l^of. Ad. Schmidt. : S 0 45.0 6 H, ô 42^5 ü H ô 4o!o 0 H 5 o 37.5 0 PI S .35°0 Ö H 0 o 32.5 0 H 130.0 132.5 135.0 r 2=34:6 3|49°47-'5 137.5 140.0 142.5 41.3 io^57°07;4 26640.2 2"45;3 7|5i°4i:4 Us768'.2 6^48°45:o 19728.9 145.0 i3''o6;4 56°22J5 Y 26559'.o These values put into linear equations for horizontal force and dip, and })arabolic formula for declination give residuals whose maximum values are 28.' 6 for the horizontal * force, 16. '(3 for the dip and 16.'4 for the declination : put into quadratic form thev come out MAGNETIC SURVEY OF JAPAN FOR THE EPOCH 189Ö.0. 3o r,= 2° 48:50 -3:90j;.+ 11:03 j^- -o:380( J/.y- + o: ll4(J/)(JvO-o:i3.Xj^)- + .44 ±.14 ±.14 ±.04:3 ±.083 ±.041 ti=r)r 23:.3S- 8:41 J/+ <^'):7GJv^-o:oo:h J/0' --<"''iGO(j;o( Jç^)-o:r.7-2(Jv-)- ±.65 ±.20 ±.21 ±.064 ±.122 ±.060 H = 29069: 4 - 49!72 j; - 404: 60Jçf- 0 141 G(J?.f + 6:544( J/)( 4^) - 5: 680(4^)- ±2.0 ±0.62 ±0.64 ±0.194 ±0..''>74 ±0.184 where j;. = (;.-138°)° and, J^=(^-37°)° expressed in degrees. The values calculated from these expressions are compared with the given data in Table VI., TABLE VI. MagiKitic Elements calculated as Quadratic Functions of Longitud(^ Latitude, from the Data given hy Splierical Harmonics for 1885.0. and No. Declination. Dip. Horizontal Intens ly. Data. Cal. Dif. r>ata. ( al. Dif. Data. Cal. Dif. I 2° o5{6 2° 04:5 I'l 46° 56:0 46° 57^4 -1^4 31375-9 31381-9 -6io 2 2° 0.:i:6 2° 03^2 0.4 46° 18:5 46° 19^1 -0.6 31009.1 3100S.9. 0.2 3 4 2° 34:6 2° 36:0 -1.4 49° 47-5 49 45'S 1-7 30195-5 301S8.S 6.7 2^ 32:8 2° 33;? -0.9 49° 27^1 49° 25;6 1-5 30043-9 30040.6 3-3 5 2° 26:2 2° 26:7 -0.5 40° o6!2 49 05-4 0.8 298^8.0 29887.2 o.S 6 7 2° 14:9 2° 14^9 0 48^ 45 '0 48 45^2 — 0.2 29728.9 29728.6 0.3 2° 45'-3 2° 45^1 0.2 51° 41:4 51 4<'3 0.1 2876S.2 28771. 1 -2.9 S 3" 14:3 3° 13-6 0.7 54° 27:0 54 29:0 — 2.0 27740.3 27742.6 -2.3 9 2° 59:2 2" 58^6 0.6 54° o6f2 54 06:7 -0.5 27657.6 27660.6 -3-0 3° 41^3 3° 4'-'3 I.O 57° 07^4 57° 08:3 -0.9 26640.2 26643.1 -2.9 II 3- 06:4 3° o7'o -0.6 56° 22:5 56° 21:7 0.8 26559.0 26555-7 3-3 12 3° 51:2 3° 5 1 -'8 -06 59° 15-8 59° 15^0 0.8 25473-6 25472.4 1.2 34 A. TANAKADATE. iVoni wliieli we see tliat tlie quadratic formiilre are sufficiently near for the purpose. Some of the coefficients whose values are less than probable errors may be omitted; but since the omission of only one or two terms little lightens the labour of com- putation, they are all kept for the sake of uniformity. The reduced values of mapiietic elements in 241* stations which were seemingly free from large local disturbances w^ere treated in the same manner and gave r,= .5° 03:i5-8.'274J;. + 17:36r)J^-0:649J7^-0^23GJlJ^-0:075J^' + .68 ±.291 ±.34.'5 +.09G ±.187 ±.103 ^ = 50° .50.'G1 -7:578 j;.+ G8:253J^ + 0.'296JÎ^-0'43SJIJ^-- 0.482 J^- ±.58 ±.247 ±.292 ±-081 ±.158 ±.087 H=2940L4-74!97J;.-362!4.5Jç^ + 3l497J^--l!316JlJ7'-4.331Jp ±8.1 ±3.45 ±4.10 ±1.141 ±2.216 ±1.222 wdiere j;.=(>^-138°)° and J^ = (^— 37°)° expressed in degrees. Expressed in minutes tliey l^ecome 0= 5° 03a5-0:i379Jyî + 0:2894Jçr-0:0001803Jl2 - 0:00006.57 JlJ^- 0:0000209 J^- ^=50° .50:61-0^263//;+ 1. '1376 J^ + 0.'0000821J^- - o:oooi2i8 j;j^-o:oooi340J^^ H =29401^4- 1.2494J;. - 6!o409J^- + 0^0009713 Jl- - 0^0003656 j;j^ -0.0012032J^c^' The computation was carried in dujilicate beside being con- trolled in the usual way. The mean probable error of a single observation is * These stations are distinsuislied bv non-braeketed nniul)ei's in Tables XV and XVI. MAGNETIC SURVEY OF JAPAN FOR THE EPOCH 1895.0. 35 + 6' 46 in the Declination, ±5:47 „ „ Dip, + 73.' 2 ,, „ Horizontal Intensity. The probable errors of the empirical coefficients are not in strict sense the result of accidental errors of observations, but are chiefly due to the amount of local disturbances ; if we omit a few of the stations which give large residuals, they will be greatly reduced, or if we include some of the stations that were omitted in the equations of condition they will be much in- creased : they are put here simply to indicate some measure of certainty in the values of these coefficients calculated by the definite method, and also to show the danger of applying these formulae to too large values of co-ordinates ; their extreme amounts within the country are : — at \j. 33, or Table V with Tables VII, IX and X below, we notice that they differ by a far greater amount than can be ascribed to errors of observations or to secular variation. Whether this is due to want of terms in the harmonic exjmnsion or to that of data in this part of the globe remains still to be seen. 38 A. TANAKADATE. TABX.E JJcclinations at 1895.0 at the Intersections of entire Degrees 0 = 5° 3.'15-8:274(;.-138°)° + 17.'365(^-37°)°-0:649 121)^ m)' 131° i:}-,>° i:J3° IU° I 135° 13()^ 137' 4«^ 45° 44^ 43^^ 42° 41° 40= 31)° 38' 37^ 36° 35° 34= 33' 4° 5^S 32' 31' 5° 28.3 7-J - 17<5 5° I/.'l 6J3 5° lofS 7^6 5° io!6 "'« 5° 9'/ 2^2 5° 7^5 3^5 5° 4.'o 4's 4° 59:2 ea 4° 53'! 7:4 — lOfd 1 i**'» — JSf(; — is'.-.i IS'l 17^8 — 4° 50:9 0^7 4° 51:6 '''7 4° 50:9 2^04° 48:9 :r2 4° 45:7 4r« 4041:1 y.s 40 35:3 7- — ]9r4 — 19^2 — isra — isre — isrö isr2 isfo — 4° 29:4 2-1 4° 31:5 ory 4° 32:4 "'4 4° 32.0 >^7 4° 30.'3 -I 4° 27:2 4r:-, 4° 22.'9 5'« 4° \f.^ ern 4° 9:6 2:4 4° 12.0 1-1 4° 1 3- 1 "■- 4° 1 2.9 i'-5 4° 1 1-4 2-'^ 4° 8.'6 4ri 4° 4:5 3°49'6 2; 3'>52:3>v'3°53:6 >o or>'r ../,, -.o 3^29:5 2ri. 3" 32:41'.^ 3 34-0 -,0 - t'^ 0 DJ-/ ^, ;. 129' 130° 131° i 132° 133° 134' 135° 13(>° ; 137 MAGNETIC SURVEY OF JAPAN FOR THE EPOCH 189Ö.0. VII. of Longitude and Latitude, calculated by the Formula, {(; - 138°)°;-- 0:23 G(;- 138°)°(^-37°)°-0.'07rj { {ç - 37°)°} - 39 138° 139° 140° Ul° U2° 143° 144° 145^ 14(> 6°4i-3 — If) a — 4() 6° 40 .'9 H '7 6° 26.'2 16 '0 6° IO.'2 - 1')',-, IS '3 \ lô'l — 45 6° 25:414-56° io.'9i5's5° 55:1 i7'o5°38.'i is'4 5° 19^7 in-r 5° o.'o 44^ I 6° 22.'6 i2'!i 6° 9.'; 14-25° 55:51.^05° 39:9 ifi'sgo 23'i is'i 5° 5b ifl'S4°45.'5 6° 6'.6 v2'- 5° 53:9 14-0 5° 39:915^3 5° 24:6 5° 50^4 1-".^ 5° 37:9 13'S 5° 24:1 5°44:9io'!i 5° 34^0 12-2 5° 21^8 13^65° gs - IR'7 — ifi'5 1 — if.rn 1 ifi'fl — 5° 28.'2 10-7 5° 17:5 ]2'n 5° 5^5 13-34° 52.'2 - ]ß-<) j l(i'7 16 f4 If) '2 5° 20^4 fl'i 5° 1 1. '3 1«--. 5° o.'S 11-7 4° 49.' I 13:1 4° 36.'o - 17^2 '■ i7'i IT) 'S — ir,'r. - 5° 3:2 !''n 4° 54:2 in.-2 4° 44:0 n'ô4° 32.'5 - i7'ö i ■ 17'2 i7'n ir,'7 — 4° 45:7 S-7 4° 37:010-04° 27:0 11-24° 15:8 - 17'fi i 17'3 17'1 Ki'il 4° 28:1 s-4 4° 19:7 0-840 Ç)'c) 11-03° 58:9 - 17^7 17'ö 17^3 - 4° I0'4 S-2 4° 2:2 9-6 3° 52:6 13S° 139^ 140^ 14r 43^ 42° 4r 40^ 39^ 38^ 37' 3(>° 3.'/ 34^ 33^ 32^ 3r 142 143° 144° 145^ 14«^ 40 A. TANAKADATE. TABLE Annval Variai worn of Decliiration at tlic Intersections of entire Dec;rees of Lonj^itude and Latitude 129° 130° 131° 132° 133° 134° 135° 136° 137° 4()° 1 j 45^ 44° 43° 42° 41° 40° 39° 3S° I -'38 37° 3(;^ 35° ifio I. '09 0:84 o.'83 0:83 0:83 0.'82 o.'8i 1 o'M 0:55 o'55 o'55 o'54 o'54 0:53 0.'52 34° o.'25 0.'26 o'.26 0^26 o.'26 0:25 0.'24 o'23 33° — o.'o4 — o.'o4 — o.'o3 — o'o3 — o.'o3 -0.03 — 0.04 — o.'os 32° -0:32 -0:32 -0:32 -0:32 - 31° -0:61 — o.'6i — o.'6o ^ ;. 129° 130° 131° 132° 133° 134° 135° 136° 137° MAGNETIC SURVEY OF JAPAN FOR THE EPOCH ISO.'i.O. 41 VIII. Jo CMlculated by the Forinuhi _|-= 1.'08- 0.'01.X/.-138°)° + 0:288(^-37°)°-0.'00i;3{(/.- 1:^,8°)°}-. 138° 139° U()° Ul° U2° U3° 144° 145° 14(>° 3-59 4(>° 3-33 3-30 3-28 45° 3-04 3 '02 2-99 2. '96 2-93 2^89 44° 1 2:77 ^•75 2:73 2 '70 2. '67 2:64 2. '60 43° 2:48 2^46 2. '44 2.'4I ! 42° 41° 40° 2^19 2:17 2:15 1-93 1:91 1^89 I. '86 1 1^64 r'62 1:60 I. '57 39° 1:37 1^35 1^33 I '3 1 I '29 38° 1:08 1 1:06 I. '04 lb2 37° 0(79 o'so 0'22 0:78 0:76 0-74 36° o'49 0-47 045 35° 34° 0^20 o'lS 33° 32° 31° 138° 139° 140° Ul° UT 143° 144° 145° 140° 42 A. TANAKADATE. TABLE Dipfi at 1895.0 at the Intersections of entire üegrees 0 =--50° 50:Ci - 7:57S(;. - 138°)° + G8.'253(v- - 37°)° + 0.'29ß VIS)' w w VM)' \U V^2' 133^ 134° ! 135^ 136° 137° 440 43^ 4:2° 41 40° ?A)' 3S^ 37° ?AV 35° 34^ 52° 6.'7 s'" 51° 6:9«^^5o°58'5 •'■' 69f0 09 r2 50° 35'4in'-i5o° 25;oo's5o° 1 5^2 0-2 50° 6'o^^7 49° 57'3''"49°49-3 "'-' — "rl'A 71 .'fl 71 r.") 71 '1 7(1.'.') 71) n — 49° 33.'6ior(!49° 23'o9;o49° 13; 1 9^49° 3.'7s^'*48° 54.'9si48° 46.'87rfi48°39'2 7^0 7r.'S i 7^-5 72^9 72'4 7K9 ! 71 '6 71 '1 48° 3o.'5io'748° i9^Si"'i48° 9'79rô48° o.'2s;o47° 5i:3sr:!47°43:o7's47° 35.'27'i47°28{i e^e 75 a 1 7-1 '7 ! • 7-1 f2 7".'S 7:; '4 7:'.'Ü 72^1 - 33° 47° 26^210^847° i5{4ior:!47° 5.'i 9:^46° 5 5:5 on 46° 46^48-546° 37'97«46° 3o'o7;346° 22'7 32° 3r 45° 59-3 >^'H5° 49-5 «'H5°4o'2^'H5° 3i'6 i 77a 7Gf7 76ri - 44° 42'29M44° 32.'8 .^'744° 24^1 129° I 130° I 131° 132° 133 134^ 135= 13()° ! 137° MAGNETIC öUilVEY Ol' JAPAN I'OK TUE EroCll 1895.0. 48 IX. of Longitude and Latitude calculated Ly the Formula {(/-138°)°]--0:43S(/-1.38°)°(^-37°)°-0:4^2{(ç?-37°)°}^ 138° 139^ UO^ UV \ U2' U3- i IW UÔ' U(\' 59° 44-5 58° 55:20^58° 46:2 s'5 5 8° 37:7 — 5!)r7 r,:);3 — 5S's • — 46^ 45° 57°55-5^^^«57°46-9s-»57°38-'9-^57°3i-5«'^57°24'7«^^57°i8.'5 57° 3'5«^-56°54-8'^^^56°46.'7-''56°39'i''^"56° 32:20^56° 25:8r,:s56° 20.0 44° 43' 56° i:5«^«55°53:2:rr55°45:5rn55°38:4 — CSn l:2'i; j (i2'2 54° 58.'47^s54° 5o:67':i54°43.'3 j i — M'i) — ecu; 1 (■,:'>'] 54° 2:4^:053° 5447:453° 47:00^853° 40:2 — Go 'A 11} '9 M'r> 04 '1 52° 57:07^552° 49:5 7:052° 42:5«M52° 36:1 5i°58:47r75i°5o:77'25i°43:5c.35i°37.'otiu5i°3i'o — (17 's ^ — ! — 67:4 wi'!i — m'f) - 50° 50:67:« 50° 43:3 «'7 50° 36:6fi': 50° 30:5 49°4i:9g:9 49° 35.'o' 35' 34' 33' 32' 31' 14()^ 44 A. TAXA K A DATE. TABI^E Ilm'hontal Forces in C.G.S. at 1805.0 at tlie Intersections of entire H =2940l!4- 74;97(/ - 138°)° - 3(J2!4.5(^ - 37°)° + 3!497 129° 130° 131° j 132° 133° 134° 135° 136° 137° 46° 45° 1 44° 43° 4-2° 41° 40° 39° 38° 37° i .29114 79 .29565 ^•5 .29480 79 36° 1 .30327 112 .30215 "■> .301 10 !*s .30012 01 .29921 S4 .29837 ", 35° •30787 n.^ .30669 111 .30558 10-1 .30454 »■ -30357 S'J .30268 So .30185 76 34° .31242 i-M .3III.S 111; .31002 11(1 .30892 wi .30790 ;•'; .30694 -^S .30606 ^- .30524 '-• 33° 32° .31692 1 1 1 20 .31563 122 .31441 "0 .31326 108 .31218 1 ui .31117 Jo .31022 ^' .30935 .31876 "21 .31755 iK^ .31642 !"- .3 "535 1 31° .32181 1:20 .32061 11:; .31948 9 129° 130° 131° 132° 133° \ 134° | 135° j 136° : 1 ! ' 137° 3IAGNETIC «ÜRVEY OF JAPAN FOU THE EPOCH 1895.0. 45 X. Degrees of Longitude iuul Latitude calculated by the Foruuila {(;.-13S°)°}--L'3l6(/-138°)°(çî-37^)°-4.'331((çr-37°)°}-. 138° l:il)° U0° ll^P U2° U3 IW U5° U()^ •25497 — 442 — .26000 «1 .25939 55 .25884 ■ 431 1 4:!2 435 — 46° W .26431 eu -26371 52 .26319 -Ifi .26273 39 .26234 32 .26202 - 423 ■ 424 425 1 42« 428 1 430 - 44c .26919 65 .26854 5» .26795 51 .26744 45 .26699 37 .26662 3U .26632 43^ .27332 Ü4 .27268 57 .27211 5U .27161 I I 404 ' • 405 40t; - 42° .27736 63 .2y6y3 5.1 .27617 .28200 69 .28131 61 .28070 55 .28015 ■ 385 387 3S8 390 — 4r .28585 67 .28518 60 .28458 53 .28405 - 377 378 ' 379 ! 380 — .29035 73 .28962 60 .28896 59 .28837 52 ,28785 3Ufi 1 308 369 371 - .29401 71 .29330 65 .29265 57 .29208 359 359 361 362 - .29760 71 .29689 63 .29626 56 .29570 349 [- 351 ^ 352 ^ 353 - .30109 69 .30040 62 .29978 55 .29923 341 312 344 - .30450 68 ,30382 60 .30322 40° 39^ 38° 37° 36^ 35^ 34^ 33^ 32= 3P 138^ 13»^ U()° UV U2 U3° U4° I 145° 14()^ 46 A. ÏANAKADAÏE. TABLE Total Forces in C.G.S. iit 1895.0 at tlie Intersections of entire Degrees of Longi- MAGNETIC SURVKY OF JAPAN FOE THE EPOCH 189.").0. 47 XI. tnde and Latitude calculated from the Foriniil;o for Horizontal Force and Dip 138° 139° UO' UV 142° 143^ ;o599 144° 145^ 14(>^ 46< .50363 S-' .50028 "<»■ .49722 45° •49773 -^"^ 49463 -■^" .49183 2'^i -48932 224 .48708 mii .48512 44^ .-,82 ■ 1 .v.: 1 .534 ] r,V2 491 — ] 471 - .49504 "13 .49191 2S.-. .48906 2--: .48649 229 48420 2(i:; .48217 IT'-. .48O4 1 43^ III - r,!»; 1 .->72 ] .548 ■'52« .48908 2.89 .48619 2fil .48358 2.3.5 .48123 .-)S4 ."il'id 540 — .48324 2<;.-, .48059 -^' .47818 .48023 270 .47753 24,5 .47508 220 .47288 .47444 249 .47195 225 .46970 202 .46768 - 565 1 .54« — H .527 .510 — .47132 253 .46879 2.30 .46649 200 .46443 1S.^ .46258 .46562 233 .46329 212 .46117 IS9 .45928 ■ 5.53 536 518 503 — .46009 21(5 .45793 194 .45599 1:4 .45425 .45472 200 .45272 179 .45093 i->n .44934 .44950 184 .44766 lfi4 .44602 42^ 41' 40^ 39^ 38^ 37' 36° 35^ 138^ 139^ 140° i 14r 142' 143° 144° 145° 146' 34^ 33' 32' 31° 48 A. TANAKADATE. TABLE Northward Forces (X) in O.G.S. at 1S9.').0 at tlie Intersections of entire Degrees of ; ^ 129° 130° 131° 132° 133° ! 134° 135° 13(>° 137^ 46^ 44c 43<^ 42^ 41° 40^ 39° 3S° 37° 30° 35^ 34^ 33° .28982 .29440 SI .29359 72 — 3fi8 369 .30204 ni .30093 K'" .29990 ft"' .29895 S7 .29808 SO .29728 71 .30677 US .30559 110 .30449 102 .30347 M .30253 S.; .30167 Tfl .30088 n - 344 ^45 1 :î47 34« 1 348 \ 34!) 1 V.^1 .31146125 .31021 117 .30904 lOS .30796 10] .30695 04 .30601 S,-, .30516 " .30439 TO 3:4 33R i 337 I - 337 ' 33.S \ 3411 341 1 .31612 132 .31480 m .31357 110 .31241 10.S .31133 100 .31033 02 .30941 8-1 .30857 325 32*; ;'.2S ' 321 — 32 3r .31805 122 .31683 114 .31569 "•" -31462 - 316 317 318 .32121 121 .32000 113 .31887 ^ -I 129^ 130° i 131° 132° 133° 134° 135° 13(>° 137 MAGNETIC SURVEY OF JAPAN FOR THE EPOCH 1895.0. 49 XII. Longitude and Latitude calculated from the Formulas for Horizontal Force and Declination. 13S^ 139° 140= Ul U'2' u:r IW U5= U(V —53-4 .25823 4S .25775 ^n .25735 - 44-2 4^:; 1 4 jr. - w 45^ .26265 4: .26218 411 .26178 -is .26146 2Ô .26121 IS .26103 ~ 4S:i 434 ■ 43.> \ 435 43(1 437 - 26752 Ô4 .26698 4fi .26652 39 .26613 32 .26581 24 .26557 ^" -26540 43= .27176 r,■^ .27123 4;-, .27078 3s .27040 - 4:r> 417 417 - .27592 52 .27540 45 .27495 ^ 4(17 4((7 --I 40s — .28058 5,, .27999 52 .27947 44 .27903 3il7 3(17 j Snn sfii) — .28455 5-' -28396 5(. .28346 44 .28302 3.SS \ 3sfl 3SI) . Sin — .28909 '■■'• .28843 5S .28785 511 .28735 ■^- -28693 37S 3f<0 • 3.S1 381 — .29287 «4 .29223 57 .29166 5I( .29116 .29657 64 .29593 5(; .29537 4« .29488 3ri(J ■ 362 3?2 3(!3 — .30017 62 .29955 •'■"' .29899 4S .29851 352 U- 352 [-- 353 - .30369 62 .30307 55 .30252 13S° i 13î)= 140= 141 42= 41' 40= Sd' 38= 37= 36= 35= 34= 33^ 00 32 3r 142= 143 144 145° 140 50 A. TANAKADATE. TABULE Westward Forces (Y) in C.G.S. at 1895.0 at the Intersections of entire Degrees of if 129° 130° 131° 132° 133° 134° 135° 136° 137° 4ß° 45^ i 44° 43° 42° 41° - 40° 39° 38° .02776 74 ... 1 37° .02723 62 .02661 72 36° ■02716 s .02718 "• .02689 3 9 .02650 -19 .02601 fiO .02541 71) 35° 34° 1 .02602 4 .02598 15 .02583 -'« -02557 3 7 .02520 48 .02472 5S .02414 fiS .02445 10 .02455 1 .02454 1-5 .02441 ■^■'' .02418 "-1 .02384 -1« .02338 » 3 .02282 WÎ 33° .02265 2 i .02289 ]■! .02303 I .02304 10 .02294 2 1 0 .02274 3 2 .02242 4 3 .02199 32° .02127 17 .02144 5 .02149 7 .02142 - 31° 1 1 .01961 19 .01980 ^ .01988 129° 130° 131° ! 132° 133° 1 134° 135° 136° 137° MAGNETIC SURVEY OF JAPA:>Î FOR THE EPOCH 1895.0. 51 XIII. Lon^àtiide aiul Latitude calculated from the Fonnul;e for Horizontal Force and Declination. 13S° 139° 140^ UP ! U2' IW IW U5= U(>' .02970 46^ .03025 11V .02908 1-w .02782 45° .02957 31' .02840 r2i^ .02714 1"4 .02580 1« .02436 15-' .02284 - 74 ! 7-1 i 74 74 74 74 - W .02990 107 .02883 117 .02766 1-^G .02640 13-1 .02506 1-» .02362 152 .02210 43^ .02909 I'l: .02802 Uli .02686 i2"> .02561 .02822 106 .02716 11c .02600 - 93 1 !W i 'Jl — .02825 w .02729 100 .02623 in .02509 - ]00 <)9 i 97 1 9S — .02725 95 .02630104 .02526115 .02411 - ]i)7 ]n.5 104 1 102 — .02702 S-1 .02618 93 .02525 103 .02422 113 .02309 1 i • ]i3 1 — 111 1 no ! ]09 - .02589 Ö .02507 92 .02415 102 .02313 ■ ns — 117 1 — ne — 110 — .02471 81 .02390 91 .02299 101 .02198 • 125 ! 123 ■ 122 121 — .02346 '9 .02267 90 .02177 100 .02077 130 129 127 - .02216 '8 .02138 88 .02050 I3S° 139= 140= ur 42= 41= 40= 39= 3? 3«=^ 35° 34° 33° 32° 31° 142° ! 143° 144° 145° 14(>^ 52 A. TANAKADATE. TABLE Uinoard Forces (Z) in C.G.S. at 1895.0 at the Intersections of entire Degrees of Longi- c 121)° 130° 131° 132° 133° 134° | 135° 136° 137° 40° U 4P i 40° 31>° 3S^- 37° -.374142S8 1 — 1 — .36662 290 — .36372 26R \m — •36907- '■•--•36545=' ?8 — .362073 '^-•35893 2J1--35602 268-.353342- 5^ 35° — .36123362-.357613S7— .35424314-.35110291— .34SI9270-.34549247-.343O2 2- î(î 34" -•353233 ^.9-.3496433n-.346283i4-.343i4292-.34022 27i-.3375i249-.33502L -'^-•332742 IS 33° — .345 IOS57 — .34153335 —.33818314 — .33504292-.332 12 5 7O-.32942Î j .31— .32691 1 230 — .32461 1 32° — .32995 312-.32683 292-. 32391 27. —.32 120 31°' ' 1 -.3iS4929i-.3i558 2:i-.3i287 1 Ç 129° 130" 131° 1 132° 133° ; 134° j 135° 136° 137° MAGNETIC SURVEY OF JAPAN FOR THE EPOCH 1895.0. 53 XIV. tilde and Latitude calculated from the Formulje for Horizontal Force and Dip. i:^S° 139^ UO' Ul° I U2° U3° IW UÖ' Uii' f •43705 .43134356 — .427 78•.•■i^ — .42454 \__ I 'Jo9 ' !i:;i 1 905 46^ 45° -.42i75">L'8 — .4i847i!w — .41549209 — .4 1280 2-!o — .41040213 — .40827 960 j 934 j 910 ! .SSfi 865 844 — — .41546331 — .41215302 — .40913274— .40639245 — ,40394219 — .40175192 — .39983 L ' : I I I — OSS \ 9(i2 ■ 937 913 - W 43^ •.4055830,3 -.40253 277-. 39976250 — .39726 1 I 986 ! 961 1 939 - .39572 2M1 -.39292 255 — .39037 9S4 \ 962 ' 941 .3887 I -'S3 -.38588 258 -.38330 234 -.38096 1005 [-- 984 ■■ 963 ■ 942 -.37S662G2-.37604237 — .37367213-. 37 154 — 1003 '< 982 ■ 1 962 1 943 .37126263 — .36863241— .36622217 — .36405 19-1- .36211 ' I I 1020 1 1000 -\ 980 962 - .36106243-. 35863 221 -.35642199-. 35443 1017 998 979 961 .35089224 — .34865 202 -,3466318! -.34482 1013 995 978 ■ 901 .34076206 -.33S7OIS5-.336S5 104-, 3352 I 1010 992 975 - .330661SS — ,32878 168- .32710 42' 4r w 39^ 38^ 37' 36^ 35= 34= 33= Or* 31= 13S= 139° I 140= 14P 142 143° 144= 145 14(>= 54 A. TANAKADATE. I^^BI^E No. [3] [4] 5 6 [7] [lO] II 12 13 14 [15] 16 17 18 Ï9 20 21 Station. Tr.kyr Hatiozi . Saruliasi Kôhu Umiuokiiti Usuta Matumoto Uniati Ku ruina .. Itoigawa . Takata ... Sekivama Nagano ... liyama .... Tôkamati Observed and Calculated Values of Masjnetic Elements Konioro Miyota Karuizawa' Kutukake Ueda Kaniismva Height, in km. 0.02 002 0.1 1 0.31 0.26 1.07 0.74 0.67 0.80 0.97 0.99 043 0.71 0.69 0.69 0.60 0.00 0.00 0.56 0.38 0.31 0.16 Ye Latitude. Longitude, 1893-96 ,35 42.0 189C1.50 ; 35 41 -o 1 893-51) , 895.48135 40.0 893-52 35 36-4 893-52 893-53 893-54 35 39-5 35 59-0 ^ 36 ii.o 893-54 ; 36 893-54 i 36 893.55 !36 i 893-55 I 36 893-56 ; 36 893-56 Î 36 893-57 136 893-58 [36 893-58 36 893-77 37 893-59 ! 37 893.60 36 893.60 89361 893.62 19.7 19-5 21.7 20.8 24.0 02.3 14.0 28.0 48.0 02.5 06.8 56.5: 39-8 52-3' 09.0, 39 46-0 39 45-0 39 20.0 3S 58.8 38 34-5 38 27.3 38 2S.1 3S 26.0 38 30-5 38 38.3 38 33-0 38 15-6 38 07.7 37 59-0 37 49-5 37 51-0 37 52-0 38 16.0 38 13-5 38 12.0 38 22.2 38 44-0 Declination 5. served Calcu- lated Obs.-Cal. 4 24.5 4 27.6 4 34-5 5 05.4 4 53-4 4 16.6 4 40-7 4 47-8 4 42-6 4 43-5 5 04-7 4 49-5 4 36-3 4 57-0 4 45-9 5 08.4 5 II-7 5 00.6 4 57-8 5 07.1 5 02.1 4 24.3 4 24.2 4 28.1 4 30-4 4 34-9 4 41.6 4 45 -o 4 47-8 4 47-1 4 46.6 4 47-1 4 50-5 4 45-3 4 49-9 4 55-3 5 00.9 4- 0.2 + 3-4 + 6.4 + 35-0 + 18.5 - 25.0 - 4-3 0.0 - 4-5 + 14-2 + 4-2 - 13-6 + 1-7 - 15-0 5 05.0 + 3.4 5 02.8 i 4- 8.9 ! ■ 5 00.2 + 0.4 4 55-6 + 2.2 4 57-8 I + 9.3 4 59-3 ; + 2.8 Bracketed nuruber shows that tlie .station is exchided in the equations of condition. MAGNETIC SURVEY OF JAPAN FOR THE EPOCH 1895.0. XV. {o, fi, H, aiul I) Reduced to 189.") 0 and Sea Level. 55 Di P ^- Horizontal Force H. Total Force I. No. Ol)- Sf-rveil CalcN- hited Olis.-Cal. Oh- soi ve/ IX "V. {Continued.) (Ô, d, H, and I) Reduced to 1895.0 and Sea Level. Di P '>■ Horizontal For oe H. To al Force I. No. 0))- served Calfu- latod (»is.-Cal. Ob- sprveil Calcu- lated 01)s.-Cal. Ob- served Calcu- lated Obs .-Cal. 0 / 51 39.4 51 147 + 24^7 T 29013 V 29174 - 161' T 46766 T 46605 + 161 22 51 55-3 51 II. S + 43.5 28S51 29223 - 372 467S0 46635 + 145 [23] 5t 35-1 51 28. 1 + 7.0 29155 29II3 + 42 46921 46735 + 1S6 [24] 51 54-6 51 44-6 + lO.O 28899 28992 - 93 46846 46823 + 23 25 51 5S.2 51 25.2 + 33-0 2S992 29097 - 105 47059 46660 + 399 [26] 51 41.9 5' 43-9 — 2.0 2S924 28965 - 41 46666 46766 100 27 51 51.0 52 00. S - 9.8 29012 28971 + 41 46967 47071 104 2S 52 lO.I 52 14.9 - 4.8 28796 28881 - 85 46949 47172 - 223 29 52 09.4 51 59.3 + 10. 1 28747 29001 - 254 46857 47093 - 236 30 51 26.0 51 44.0 - 18.0 29257 29083 + 174 46930 46959 - 29 31 SO S4.0 50 12.3 + 41.7 29539 29547 - 8 46S37 46165 + 672 [32] 50 00.0 50 06.1 - 6.1 29870 29573 + 297 46470 46106 + 364 [33] 51 45-2 50 05.9 + 99-3 30 1 98 295S0 + 618 48781 46113 + 2668 [34] 49 59.3 49 57.5 + 1.8 29627 29592 + 35 46080 45996 + 84 35 50 07.3 49 57-3 + 10.0 29604 29573 + 3« 46172 45965 + 207 36 50 19-3 50 19.5 — 0.2 29443 29453 — 10 461 1 5 46133 - 18 37 49 5S.4 49 428 + 15-6 29559 2961 1 - 52 45960 45794 + 166 38 49 09.1 48 42.2 + 26.9 30217 29943 + 274 46199 45371 + 828 39 4S 57-9 48 31.9 + 26.0 29353 30002 - 649 44710 45306 - 596 [40] 47 53-3 48 03.3 — lO.O 30186 30155 + 31 45015 45 114 - 99 [41] 48 12.0 48 09.8 + 2.2 30149 30137 + 12 45232 45183 + 49 42 58 A. TANAKADATE. TAI^BE Observed and Calculated Vaines of Masrnetic Elements No. Station. Height, in km. Year. Latitude.' Longitude, Declination S. Ob- served Calcu- lated 01>s.-Cal. 43 44 [45] [46] [47] [48] [49] [50] [51] [5-] [53] [54] [55] [56] [57] [58] [59] [60] [6.] [62] 6:: Hudisawa. (Itn iVEidono .... Yosida LTmagaesi Hnzi East side Syakadake ... ,, Sainokawara near Kinmeisui, „ Sainokawara near Ginmeisni, ,, Bottom of Crater Mnravama Hiromil)ara .. „ Down Uzuragoya „Up Uzuragoya , Mituike MituikeCave ... Front of Mituike Cave. Front of Hitoana Ttimaiiwa in Hitoana Front of Hitoana Omiya .., Numazu 0.00 0.00 0-55 0.84 I. CO 3.73 3.60 3-72 3-56 0.50 0-73 0.69 0.78 0.82 0.82 0.82 0.69 0.69 0.69 O.II 0.00 1893-79 1893.81 t 1893.82 * 1893.51 t ■S93.81 "" 1893-51 t 1893.81 * 1893.52 1S93.53 1893.53 1893.53 1893.53 * 1S93.S0 t 1893.53 t 1S93.80 "■ 1S93.54 1893.54 1893.54 1893.54 1893.54 1893.54 1893-55 1893.55 1893.55 t 1893.79 * 1893.55 t 1893.82 * 1893.55 35 20.8 35 15.4 35 20.0 ;5 28.0 35 25.0 35 21.7 35 21.7 35 21.4 35 21.5 35 15-0 35 21.1 35 21.0 35 21. 1 35 22.4 35 22.4 35 22.4 35 21.5 35 21.5 35 21.5 35 13.5 35 05.0 o / 39 29.3 39 42.5 38 54.0 38 48.0 38 47.0 38 44.0 38 43-8 38 43.9 38 43.9 38 40.0 38 36.7 38 36.3 .38 37.2 38 35.9 38 35.9 38 35.9 38 35.5 38 35.5 38 35.5 38 38.0 38 52.5 4 33.9 4 17.5 4 25.2 3 29.9 4 44.1 3 05.5 3 17.6 O / / 4 21. 1 ! + 12.! 4 17.3 ^ + 0.2 4 26.4 — 1.2 4 29.6 - 59.7 4 22.6 4 25.6 4 28.9 4 28.4 4 28.3 4 28.3 4 28.3 4 27.0 4 29.3 4 29.3 4 29.2 4 29.7 4 29.7 4 29.7 4 29,5 4 29.5 4 29.5 4 26.9 4 22.2 + 15-2 -81.5 -71.7 - 4.3 + 3.4 t Epoch for the observation of S. * Epoch for tlie observations of 0 and H. MAGNETIC SURVEY OF JAPAN FOR THE EPOCH 1895.0. 59 _X_ V^. (Continued.) (d, d, H, and I) Eeduce Hi to 1895.0 and Sea Level. Dip 0. Horizontal Force H. To tal Force I. No. seived Calcu- lated Olis.-Cal. Ob- i Calcu- ,,, ,. , served luted j Obs.-tal. Ob- served Calcu- lated Obs.-Cal. - 167 49 02.6 1 0 48 46.9 + 15-7 29623 29SÖS J - 265 Y 45192 T 45359 43 48 36.3 48 39-4 - 31 29S32 29906 - 74 45114 45273 - 159 44 49 50.1 48 49-6 + 60.5 29218 29931 - 713 45299 45464 - 165 [45] 49 14.1 ' 48 59.5 + 14.6 29698 ' 29891 - 193 45483 45554 - 71 [46] 50 25.3 ■ 48 56.1 + 89.2 28S35 29909 -1074 45258 45529 - 271 [47] 59 18.8 48 52.6 + 626.2 26215 29929 -3714 51368 45507 + 5861 [48] 52 41-9 48 52.7 + 229.2 29328 29932 _ 604 48395 45512 + 2S83 [49] 59 14.5 48 52-3 + 622.2 24647 29934 j -5287 48193 45510 + 2683 [50] 47 42.4 48 52.4 — 70.0 31221 29933 + 12S8 46396 45510 + 886 [51] 48 55-8 48 45-3 + 10.5 30595 29976 + 619 46569 45467 + 1102 [52] 49 15-2 48 52.7 + 22.5 29768 29944 - 176 45594 45531 + 63 [53] 48 50.4 48 52.7 - 2.3 29700 29945 - 245 45124 45532 — 408 [54] 49 39-9 48 527 + 47-2 29937 29943 - 6 46252 45529 + 723 [55] 40 04.5 48 54.3 -529.8 34010 29937 +4073 44446 45545 -1099 [56] 48 18.1 48 54.3 - 36.2 29860 29937 - 77 44888 45545 - 657 [57] 47 39-8 48 54-3 - 74-5 29109 29937 - 828 43221 45545 -2324 [58] 46 20.8 48 53-3 -152.5 29386 29943 1 - 557 42565 45539 -2974 [59] 46 38.7 48 53-3 -134.6 26126 29943 -3S17 38056 45539 -7483 [60] 42 14.9 48 53-3 -39S.4 3«593 29943 + 1650 42680 45539 -2859 [61] 48 35-1 48 43.8 - 8.7 30275 299S6 + 289 45767 45460 + 307 [62] 48 23.0 48 32.4 1 - 94 30108 30019 + 89 45337 45340 0 63 Braclieted number showa that the station is excluded in the et^uations of condition. 60 A. TANAKADAÏE. TABLE Observed and Calculated Values of Magnetic Elements No. Station. Ileiglit in km. Year. Latitude. Lonsrilude, Declination o. Oil- i Cak-u- servcd I latcd Ol.s.-Cal 65 66 67 68 69 70 71 72 73 74 75 76 77 7S 79 So 81 [82] 84 Simizu Nisinoto Olvazaki Kôwa ... Naruiui Nagoya Macgasu Yokkaili Kameyania .... Tu Kaniiyasiro. Toba Katikawa .. Kiyusii Gilui ISakatugawa lida ... Matuô llukusiuia Noiuugi ... Takayauia 0.00 0.14 0.05 0.00 0.00 0.00 Ü.09 0.00 0.00 0.05 0.00 0.00 0.15 0.30 0.53 0.53 0.78 1.16 o.s6 0.00 * t -^93-79 893-56 893.78 893.56 893.77 893.57 893.74 S93.58 893.75 893.58 S93.71) 893.58 896.76J 893.71 893.59 893.72 893.59 893.72- 89- 896. S93.73 893.60 893-73 S93.60 893-73 893.61 893.76 893.61 893.75 893.61 89 3. 68 893.62 89377 893-63 S93.78 S93.64 893-64 )3.72) ?3-59^ 36.6S3 o / 35 00.5 35 02.0 3i 56.5 34 46.0 35 05.0 35 IO-5 35 o^.o 34 58.5 34 52.0 34 43-0 34 30-0 34 29.0 35 13.0 35 12.0 35 25.5 35 29.0 35 31.0 35 29.0 893-65 135 50-0 893-65 36 02.0 893.66 I 33 oS.o o » 38 30.0 37 50-0 37 08.0 36 55-5 36 5S.0 36 56.0 36 44.0 36 37.5 35 28.0 36 31-0 36 45-0 36 50.0 36 58.0 36 51.0 36 46.0 37 32.0 37 50-0 37 52.0 37 42-0 37 35-0 37 16.5 O / I O » ! r 4 II. 4 4 24.2 — 126 4 24.0 4 30.0 — 6.0 4 31-8 4 33-3 I - 1.5 4 35-4 4 3'-6 ' + 3.8 4 39-7 4 37-0 + 2.7 4 42.3 4 38.8 , + 3-5 I 4 40.6 4 38-8 j + 1.8 4 36.7 4 37-2 - 0.5 4 33-4 4 36.2 j - 2.8 4 28.3 ; 4 33.1 - 4-8 4 28.7 4 27.9 4- 0.8 4 26.8 4 27.0 — 0.2 4 44-5 4 39-4 ^ + 5-1 4 40.9 I 4 39.8 I 4- i-i 1 ' 4 41-7 , 4 44-4 ; + 0.3 4 43-4 4 40.2 [ + 3-2 4 34.2 4 38.5 — 4.3 4 37.7 4 37-7 0.0 4 57-5 4 45-1 + 12.4 4 56.6 4 49.5 + 7.1 4 51.8 4 53.6 - 1.8 t l^^pocli lor Uic observation o 0. * Ejjoeli lb liie observations of 0 and II. MAGNETIC ÖUllVEY OF JAPAN FOil THE EPOCH 1895.0. 61 IX! "V^. (Continued.) (o, d, H, and I) Reduced to 1895.0 and Sea Level. Dip Q. Horizontal Force II. Tot al Force I. No. Ol)- seived Calcu- i latcd Oli.s.-Cal. 01.- sei'ved Calcu- /ii „ lated '^'■-• -Cal. 01 )- served Calcu- lated OI)s.-Cal. 0 4S 33.1 48 ° 29^5 ' + 3-6 T 30153 1 Tl 30071 + Y 82 45552 45375' + 177 64 4S 38.3 48 35 -0 + 2.7 30049 30110 ! - 61 45473 45524 - 51 65 48 32.8 48 34-1 - '-3 301 10 30194 - 84 454S2 45629 - 147 66 48 23-5 1 48 23.2 + 0.3 30255 30271 1 - 16 45563 455''^3 — 20 67 48 45-6 1 48 45-3 + 0.3 30133 30159 j - 26 45710 45746 - 36 68 48 47-3 48 52.0 - 47 30186 30130 + 56 45817 45804 + 13 69 48 4S.5 48 4S.2 + 0.3 30173 30172 + I 45815 45809 + 6 70 48 38.7 48 40.2 - 1-5 30206 30224 - 18 45716 45767 - 51 71 48 33-3 48 33.7 - 0.4 30198 30274 - 76 45623 45744 — 121 72 48 34.5 48 22.7 + U.8 30205 30321 ' - 1 116 45652 45650 + 2 73 48 09.0 48 05.6 + 3-4 30345 30376 1 - 31 45483 4547S + 5 74 47 57.2 ' 48 03.7 - 6.5 30413 30374 + 39 4541 1 45448 - 37 75 48 53.7 ' 48 5^-7 — I.O 30094 30113 - 19 45774 45S1S - 44 76 48 554 , 4S 54.4 + i-o 30084 30128 - 44 45786 45837 - 51 77 49 07.7 49 10.9 — 3-2 30064 30057 + 7 45944 45982 - 38 78 49 07.6 49 09.3 i - 1-7 29903 29976 - 73 45696 45833 - 137 79 49 06.1 49 09.5 - 3.4 29S60 29942 - 82 45607 45785 - 178 80 49 10.8 49 06.9 + 3-9 29841 29951 - no 45650 4575S — loS 81 50 22.3 49 33.5 + 49-9 29614 29S41 - 227 46430 45988 + 442 [82] 49 37-5 49 47-- - 9-7 29942 29779 + 163 46222 46123 + 99 83 49 46.2 49 56.5 - IÛ.3 29S 1 9 29768 + 51 46169 46255 - 86 84 Braciieted number shows that the station is exchuled in the etiuations of condition. 62 A. TANAKADATE. No. S5 S6 87 ss 89 90 91 92 93 94 95 96 97 98 99 100 lOI 102 TABI.E Observed and Calculated Values of Masnetic Elements iStation. Gero Hatiiiian ... Nagamine Nairahama ïuruga Takeliu Olio Sioya Kanazawa Nanao .... Waziiua.. Toyauia . Mozumi . Mikkaili . Abiita .... O.syamanbe . SuUu Iwaiiai [103]' Yobetu [105] Otaru Height ill km. Year. Latitude. Longitude 0.58 0.21 0.37 0.05 0.00 0.04 1893.67 1893,67 35 48.0 1 137 16.0 35 44-0; 136 57-0 1893.6S 35 40.5 1893.69-)' ^^ 1896.54J1 136 35-0 136 15.0 ^ 35 22.5 1893-69 : 3S 39 -o , 130 02.0 »893-70 1 35 53-0, 130 ii.o '104] Hunatua 0.20 j 1893.70 35 59.0 ■ 136 30.0 ! i 0.00 ; 1893,71 136 16.5 1 136 17.0 1893.72 36 33-7 136 40.0 0.00 0.00 o.oi 1893.72 37 03.5 137 00.0 1893.73 !37 22.5! 136 55.0 1893.74 Declination 0. (jii- si-rved Calcu- lated Obs. -Cal. 4 47.0 [ 4 47-7 4 49.7 i 4 48.7 i 4 56.1 ■ 4 50.0 4 47.8 ' 4 46.5 j + 4 48.6 4 52.7 ^ - 4 52.9 4 56.1 I - 4 50.9 4 56.0 5 03.6 5 02.5 5 043 ' 5 05.3 5 II. I 5 II.8 - 0.7 5 15.4 : S 17.9 + 0.7 I.O 6.1 4.1 5-1 I.I 1.0 36 40.0 137 13.7 5 06.5 5 03.3 0.40 I 1S93.75 35 2S.0, 137 14.0 0.00 I 1893.76 36 51.0 i 137 28.0 ' I ' 0.00 I 1S94.50 ,42 33-1 MO 45,3 o.co 0.00 0.00 o. 10 0.00 0.00 1594.51 42 30.7 140 22.4 1894.52 1 42 47.31 140 13.4 1594.52 1 42 58.81 140 30.8 ! 1894.53 43 19.7 i 140 22.8 I j »894-53 I 43 19.5 I 140 33-4 1894.54 '43 12.0! 141 00.5 4 56.6 : 4 59.7 5 lo.o S 04.7 6 I I.I 6 05.9 5 51.6 6 10.2 6 02.3 , 6 16.5 6 254 ; 6 15.9 6 00.4 6 23.1 4 49 o 6 20.8 6 14.0 6 12.8 — 2.5 + 3.2 - 3.1 + 5-3 + 5-2 - 18.6 - 14.2 + 9-5 22.7 - 91.8 + 1.2 Bracketed number shows tliat tlie station is excluded in the equations of condition. MAGNETIC SURVEY OF JAPAN FOR THE EPOCH 1895.0. 03 IX]. "V". {Continued.) (o, 6, IT, and I) Reiluced to 1895.0 and Sea Level. Dip 6. Horizontal Foi ce H. Total Force I. No. Ob- served Calru- latod Olis.-Cal. Ob- served Calcu- lated Obs.-Cal. Ob- served Calcu- lated Obs.-Cal. o / 49 30.4 49° 334 - 3.0 T 29903 T 298S6 + 17' T 46051 46092 T - 41 85 49 22.4 49 3I-I - 8-7 30008 29934 + 74 460S7 46109 — 22 86 49 2S.1 49 29.8 - 1-7 29950 29985 - 35 460S7 46167 - So 87 49 07.8 49 11.4 - 3-6 30102 30117 - 15 46003 460S2 - 79 8S 49 25.0 49 32.5 - 7-5 30149 30040 + 109 46344 46295 + 49 89 49 27.9 49 47-7 — 19.8 30339 29946 + 393 466S1 46390 + 291 90 49 56.4 49 52.1 + 4-3 29895 298S4 + II 46450 46365 + 85 91 50 17.2 50 14.2 + 3-0 29704 29799 - 95 46489 46590 — lOI 92 50 45.8 50 31.0 + 14-8 29617 29665 - 48 46S23 46653 + 170 93 5 1 09.0 51 02.5 + 6.5 2952S 29459 + 69 47073 46853 + 220 94 51 32.2 51 24.9 + 7-3 29205 29351 — 146 46953 47061 - loS 65 50 48.0 50 33-7 + M-3 29337 29581 - 244 46417 46565 - 148 96 50 00.9 50 19.9 — 19.0 297S9 29652 + 137 4635S 46450 - 92 97 50 40.0 50 44.4 - 4-4 294S5 29-197 — 12 46519 46610 - 91 98 56 44-6 56 29-3 + iS-3 26687 27056 - 369 48666 49005 - 339 99 56 176 56 30.1 - 12.5 27243 27097 + 146 49092 49096 - 4 100 56 43-2 56 4^-5 - 5-3 26991 26992 — I 49188 49307 - 119 lOI 56 52-3 56 57.8 - 5-5 26790 26893 - 103 49020 49330 - 3'o 102 56 57-8 57 20.3 - 22.5 27032 26756 + 276 49584 49578 + 6 [103] 57 32.0 57 1S.5 + 13-5 26683 26746 - 63 49707 49519 + 188 [104] 57 10.3 57 06.9 + 3-4 26762 26769 - 7 49365 49303 + 62 [105] 64 A. TANAKADATE. TABLE Observed and Calculated Values of Ma2;netic Elements No. Station. Height in km. Year. Latitnde. Lonn;itnde, Declination 5, oil- f'aleu- ,,, „„, sovvod I lat,Ml Ol.s.-Cal. 06 07 08] Otaru Mvôkenzan Sapporo Iwaraizawa. 09 ! Soratipt. Tip-Yahnsi. Asahikawa. 10 II 12] Oliotnkawa 13] Porokamnikotan 14 j Masike 15 Sirasitomari 16 Huren 17 Tesio. 18]! Pösinai-pitari... '9] 20] Oknruraatoma- nai Nayoropt . 21 ]l Nuppamamoi ... 22] Wakasakanai... 23 Wakkanai 24 Soya 25 ]j Sarubntu. 25]| Esasi 0.04 0.00 0.00 0.00 0.21 0.00 o.io 0.70 0.00 0.00 0.00 0.00 0.04 0.08 0.0 1 0.00 0.00 coo 0.00 0.00 1894.62 1894.55 1894.56 IS94.56 1894.57 1894.58 1894.59 1894.60 1894.64 1894.64 1894.65 1894.66 IS94.67 1894.68 1894.69 IS94.70 IS94.70 1894.71 1894.71 1894.72 1894.73 43 "-9 43 04.8 43 12.9 43 34-0 43 26.5 43 46.5 43 43-2 44 00.0 43 51-3 44 18.7 44 34-6 44 53-3 44 50-2 44 36.0 44 23.4 4* 54.3 45 06.7 45 24.0 45 29.4 45 16.7 44 57-0 141 00.6 141 21.0 141 45.0 141 54-7 142 17.2 142 20.2 141 57.0 142 06.0 141 31.8 141 39.0 141 46.7 141 44.1 142 03.7 142 17.S 142 27.2 141 59.0 141 37.0 141 39.0 141 52.7 142 14.0 142 34.9 6 17.7 6 10.6 6 12.7 + 5.0 6 06.1 5 27.3 6 02.5 6 12.0 6 09.1 6 27.8 6 13.9 6 24.8 5 29.1 7 053 6 51-3 6 49.8 6 39-4 7 16.7 7 03.0 6 07.3 6 09.4 6 15.6 6 20.9 6 23.1 6 2S.5 6 22.8 6 155 6 09.8 6 25.0 6 33.7 Ö 37.6 6 35-5 6 26.8 6 16.3 + 4-5 - 35-2 5 50.1 6 05.6 - 15.5 5 33-2 1 5 58.0 I - 24.8 6 20.1 6 02.3 4- 17.8 + 2.6 - 6.5 + 6.9 - 9.2 - 3-7 -53-7 + 49-8 + 41.5 + 12.2 + 39 + 49-9 + 46-7 Bracketed number shows that the station is exchided in the equations of condition. MAGNETIC SURVEY OF JAPAN FOR THE EPOCH 1895 0. ()5 5C\^. {Continued.) (o, d, H, and I) Reduced to 1895.0 and Sea Level. Dip 6. Horizontal Force H. Total Force I. No. i Ol)- sprvod Calcu- hite.l Obs. Cal. Ob- served Calcu- lated Obs -Cal. Ob- served Calcu- lât eil Obs.-Cal. 57 ° oo!4 c 57 06^8 _ 64 26921 26770' + 151' 4943s' 49303' + '35 io6 57 oS.8 56 56.8 + 12.0 26496 26799 - 303 4S841 49135 - 294 107 j 57 '4-7 57 01.7 + 13.0 26482 26719 - 237 48945 49095 - 150 [•OS] 57 22.2 57 21.6 + 0.6 26577 26561 + 16 49289 49245 + 44 109 57 15-9 57 II. I + 4.8 26545 26593 - 48 490S9 49071 4- 18 no 57 30.7 57 30.7 0.0 26416 26449 - 33 491 So 49241 - 61 III 57 35-0 57 30.5 + 4-5 26595 26494 + lOI 4961 1 49320 + 291 ["2] 58 04.8 57 46.1 + 18.7 26439 26366 + 73 50005 49434 + 571 ["3] 57 34-9 57 42.2 - 7-3 26519 26460 + 59 49463 49522 - 59 114 58 15.8 58 08.5 4- 7-3 26245 26258 13 49895 49747 + 148 «15 5S 25.5 58 231 + 2.4 26135 26136 0 49915 49859 + 56 116 58 49.2 58 41.9 + 7-3 25923 26003 - 80 50071 50050 + 21 117 58 43-4 58 36.0 + 74 -6097 26006 + 91 50267 49914 + 353 [118] 58 22.8 58 20.1 + 2.7 26126 26096 + 30 49832 497 1 1 + 121 ["9] 58 12.0 58 06.4 + 5.6 26206 26179 + 27 49729 49550 + 179 [120] 58 584 58 40.7 + 17.7 257S6 25981 - 195 5C027 49979 + 48 ["21] 58' 59-7 58 56.1 + 3.fi 25779 25912 - K^:^ 50345 50217 - 172 [122] 59 16.1 59 12.7 + 34 25783 25784 - I 50453 50373 + 80 123 59 134 59 15-9 - 2.5 25759 25730 + 29 50341 50345 - 4 124 59 00.3 59 00.4 - 0.1 25754 25803 - 49 50012 50108 - 96 [125] 59 38.7 58 38.3 + 0.4 25182 25928 - 746 49830 49820 + 10 [126] or, A. TANAKABATE. T^BILE No. Observed and Calculated ValtK^s of Masjnetic Elements StMti Height in km. Year. Latitude. Loni^itude. Declination S. Ob- served Calcu- lated Obs.-Cal. o / 6 I0.6 0 1 6 07.2 + 3.4 6 00.4 5 547 5 4S.2 + 5.7 27 Poron.ai 28 ^[onhetii 29] Yfibetu 33 Nno'anii ji Aiiionai 32] Abasiri iz ^y^i-i 34 Kaiisii 35 Siliotii 33 Hakodate 37 -^r"n 3S Setaua 39 Kntn 40 Esasi 41 Hukuyama I 42 Siriuti 43 Tiril)ctn 44] Tomakoiiiai 45 Sanipt 46 Osyatinai 47] Nolinka Bracketed number 0.00 0.00 o.co o.io 0.20 0.00 0.00 0.00 0.00 0.00 000 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.10 0.00 1594.73 44 400, 142 52.9 1894.74 44 217 , '43 2J.O I 1594.74 44 14.0, 143 37.1 1894.75 44 02.0 143 33.0 1894.75 43 4S.7 143 4'^.2 1894.76 44 01.2 144 16.6 1S94.76 43 54.9 144 39.6 1594.78 44 01.4 ' 145 12.0 1594.79 43 39-1 145 o^-5 1 1894.50 4' 46.5 140 43-5 1894.51 42 07.0 140 34.5 1894.53 ,42 26.9^ 139 51.0 1894.54 42 13.6, 139 49-5 1894.55 '^^ 52-5 ] 140 09.0 1894.55 41 26.0 140 09.0 1894.56 :4i 36.3 140 25.5 1894. 58 42 20.S 141 00.0 1594.58 '42 36.5 j 141 36.0 i I 1894.59 [42 30.41 142 01.5 1894.60 42 41.2 142 13-5 1894.61 ; 42 19.4' 142 4S.O 5 57.6 5 47.3 ! + 10.3 5 4S.5 5 38.7 + 9.8 4 43-1 : 5 33.4 Î - 50.3 [ ; 5 357 i 5 24.9 I + 10.8 I 4 55-9 5 16.2 1 _ 20.3 5 04.6 5 II-9 7-3 5 46.0 I 5 53.9 5 40.5 ! 6 01.3 6 05.4 6 15.6 6 26.0 6 12.3 6 07.5 I 6 02.7 S 49.0 5 55-6 5 317 ' 5 55-0 6 08.4 ; 5 59.4 5 06.2 I 5 55.2 ! 6 01. 1 : 5 47.4 5 50-9 : 5 47-3 6 09.1 ; 5 32.7 — 7.9 - 20.8 - 10.2 + 137 + 4.8 - 6.6 - 23-3 + 9.0 - 49-0 + 137 + 3.6 + 36.4 .shows that tlie station is exchided in the equations of condition. MAGNETIC SURVEY OF JAPAN FOR THE EPOCH 1895.0. 07 _XL V^. {Continued.) {Ô, d, H, and 1) Eeduced to 1895.0 and ^iea Level. Dip 0. Horizontal Force H. Tot 1 1 Force I. No. : 1 Ob- i served ' Calcu- ! lafoil Obs.-Cal. 01.- 1 served ' Ç^}-- 0b.s.-Ca.. Ob- served tt" W-^^^ 58° lia \ 58 ° 19.2 - 5-6 26185' 26036 , + 149 49728 7 ! 49576 + 152 -1 57 5j-o . 57 57-6 - 4.6 20232 26146 + 86 49341 ! 492S6 1 4- 55 128 1 57 42.6 57 47-0 - 4-4 26289 26189 + ICO 49211 49124 4- 87 [i2y]i t i 57 29.9 57 37-1 - 7-2 26384 26280 1 + 104 49102 49070 4- 32 130 1 57 12.3 57 20.S - 8.5 26396 26362 + 34 48734 4S857 - 123 '3' \ 57 IO-9 57 30.8 - 19-9 26684 26253 + 431 49235 1 45^879 4- 35Ö [I32lr 57 30.4 57 22.0 + 8.4 26223 26283 — Co 1 48815 48739 . 4- 76 133 57 17-7 57 24 .8 - 7' 26383 26217 + 166 48828 4SÔ7S ■ 4- 150 134 57 16.7 57 03.4 + 13-3 26180 26379 - 199 48432 48509 - 77 135 55 31-5 55 4'-4 - 9-9 27456 27376 1 + 80 48505 4856S — 63 136 56 14.2 56 03.9 + 10.3 27181 27246 - 65 4890^ 4S80Û + 102 137 56 12.2 56 30.7 - 18.5 27396 27158 + 23S 49250 49220 4- 30 138 56 04.6 56 17.2 - 12.6 27306 27251 + 55 48952 49098 - 146 139 55 55-3 55 524 + 2.9 27272 27373 — 101 48672 48791 - 119 140 55 05.9 55 24.6 - 18.7 27767 27552 + 215 48529 48532 1 - 3 141 55 34-9 , 55 33-2 + 1-7 27459 ' 27465 - 6 48580 48556 + 24 142 56 30.S 5^ 14-7 + 16.1 2681S 27125 - 307 48606 48817 - 211 143 5^ 47-9 56 25.9 4- 22.0 26927 26981 - 54 49' 75 48797 + 378 ;[144] 56 26.0 56 16.4 + 9-6 269S6 j 27000 - 14 48^08 48628 ' 4- 180 ii45 56 33-2 5f> 25.9 + 7-3 26932 ' 26914 4- 18 48864 48675 4- 189 146 55 5^-3 55 59.5 — 3-2 27099 27036 + 63 48384 4833S 4- 46 [147] ß8 A. TAXAKADATE. TABLE Observed and Calculated Value« of Mao-netic Element« No. Station. [14S] Urakawa. 149 Syoya 150 Muv'oro... 151 152 '53 '54 155 [156] 157 ;[i5S] i 1['59] p6o] :[.6l] Tyurui .. Meiuiiro Otasn ... Sycrusaiu Asyoro...., Ötu SiranuUa Sibetya Alusanupuri ... Sinryu ., Nenmro 1 162 Seiidai, 163 164 165 166 167 [16S], ICoguta Gaiiioi) Midzusawa Ilanaiuaki Morloka Nakavaiiia Height I Year. , Latitude. Longitude, in km. Declination 0. Ob- scivc'd (■alcu- lated Olis.-Cal. 0.00 1S94.62 42 08.8 142 4S.0 ! 0.00 1894.63 42 01.5 143 16.5 o.co 189^.65 42 1Ô.4 143 iS.o 0.00 1S94.65 42 33.2 143 0.08 1S94.66 42 55.0 143 0.27 1894.67 43 04.0 142 0.05 0.23 0.00 0.00 0.05 0.46 0.00 0.03 0.00 0.0 1 0.02 0.06 o.'3 0.-13 1894.69 42 54.3 143 1594.70 43 17.5! 143 1894.71 42 40.5 143 ! 1894.72 42 56,3 144 '894.73 43 17-7 144 1894.74 43 37-2 '44 1894-75 '43 03.0 144 1894.70 ^ 43 20.4 145 189449)! 1894.82!' ,1 o ' 1895-49 h^ ^5-8 140 1S95.69J I 1895.49 38 31.5 141 1895-50 38 44.0 141 1895-51 J'J 07-6 14' i I 1895-51 39 25.0^ 141 Î 1895-51 39 42.5 141 1895.52 40 03.3 141 18.0 00.0 49-51 37.53 39-0 06.0* r, 35-5^ 25-5^ 6 05.4 5 30.0 + 35.4 S 36.2 5 20.5 + 15.7 5 18.6 5 23.9 I - 5.3 5 21.7 5 28.2 - 6.5 5 48.1 5 38.7 + 9-4 6 05.3 5 43.8 +21.5 26.8 5-5 50-5 36.0 5 42.0 5 34.0 + 8.0 5 5y.o 5 24.2 + 34.8 i 5 04.7 S 20.4 ' - 15.7 5 42.6 5 16.9 + 25.7 5 1 7. 1 5 24.S - 7.7 5 34.6 5 08.7 + 25.9 4 04.9 4 58.5 - 53.6 52.0 1 5 o5.2 : 4 55.1 + II. I I I 04.0 1 5 14.5 4 5G.9 + 17.6 06.0 5 13-3 4 59-9 : + 13-4 8 ' ! 05-5 5 12-3 5 o6-4 ; + 5-^ 06.5! 5 29.4 5 10.4 i +19.0 I I 07.51 5 32-5 S 15.4 + 17-1 16.5 S 5 48.5 5 19.1 i + 29.4 Brackeled number shows that the station is excluded in the equations of condition. MAGXETIC SURVEY OF JAPAN FOR THE EPOCH 18Ü5.0. _XL v' . {Continued.) (o, 6, H, Hiul I) Reduced to 16!).3.U and Sea Level. 69 Di P 'J- Horizontal Force F Tut al Force 1. ! No. 1 Ob- i Caleu- sorved latcd Obs.-Cal. Ob- S"'^'"- ' Obs. Cal. Ob- 1 '^^ <^'-^^"- 1 O / 0 55 50-9 , 55 4S.'7 : + 2'. 2 27192' 27109' + &i 48437 48244 + 193 ['48]; 55 39-1 55 3S.0 ' + I.I 27138 27138 0 48098 48076 + 22 149 55 53-4 55 53.0 1 + 0.4 27II2 27034 + 7S 48347 : 1 48199 + 148 150 56 12.7 : 56 1 1 0.0 , 4- 2.7 26959 26917 + 42 i 48475 48345 + 130 15' 56 33.6 56 34-1 - 05 26S09 26779 + 30 4Î1649 48605 + 44 152 56 40.6 , 56 44-4 - 3-8 26767 26724 + 43 4S724 48727 "~ 3 153 56 27.4 56 33.7 ; — 3-3 26737 26766 - 29 48387 4S509 — 122 151 56 4-^-3 56 52.2 1 - 9-9 26628 26592 + 36 48508 4^655 - 147 155 56 16.7 56 15.0 + 1-7 27044 26S5I + 193 48714 48330 + 3S4 [■56] 56 40.0 56 27.8 + 12.2 2Ô670 26721 51 4S534 4S366 + 168 157 56 38.S 5Ö 45-9 - 71 26483 26551 - 6S 48166 48144 - 278 [•5S] 56 47-4 57 06.2 - 18.S 26566 26419 + 147 48504 4S643 - 139 [•59] 57 17-2 56 29.7 + 47-5 2659S 26646 - 48 49216 48270 + 946 [160] 57 29.8 56 42.3 + 47-5 255S4 2649S - 914 476II 48270 - 659 [i6i] 51 57-3 51 55-2 + 2.1 2S619 28746 - 127 ; 46438 46608 - 170 A 52 09.2 52 11. 1 - 1-9 2S82Ô 28635 + 191 ; 46982 46705 + 277 .03 52 42.8 52 24-5 + 1S.3 28179 28554 - 375 i 46516 46808 — 292 164 52 4-.4 52 50-1 - 7-7 1 2S393 28404 - II 1 4OS61 47019 - 158 165 53 00.3 53 08.8 - 8.5 1 1 28 I 94 2S29I - 97 \ 46854 47170 - 316 166 53 "-8 53 27.4 - 15-6 ; 2S267 28177 + 90 ; 471^6 47323 - '37 167 53 33-0 53 48.6 - .5.6 j 2S0S1 28032 + 49 1 47265 47474 - -09 [-68] 70 A. TANAKADATE. TABI.E OUserved and Calculated Values of Ma-iiiietic Elements Ni). ; Staliuii. Hciglit I Ytiir. Latitudo. Longitude, in km. [169] Ilatiiiohe. 170 Koininatotaira.. _(in iSameiira) [171] Ono 172 KiiziiiiEikutvu [173] Akka 174 Auazawa [175] Iwaizuiui [176J Miyako [177] Oguni.riikutvfi, 0.04 i 1S95.60 40 ji.o 141 31.3 0.00 ^ 1895.53:40 32.3' 141 34.3 0.20 I 1895.53 40 15.2, 141 37.8 0.00 I 1895.54 4° 11-6 141 47.8 !" ! I 0.10 , 1895.54 '39 59.3; 141 44.0 0.3 J? 178 Töno ! 179 Kaiuaisi .... I 180 ; Kcyoniiuiiia 181 I [182] .S3; 184 :' [1S5] [186J XS7' 188 1S9 Ibinoiiiaki Ikiisazawa iSiiiiüiniKii Yukutc ... Kakiidate Kariwanu , Akita ... llonzvû ^<'s.-Cal. 5 35-7 5 31-9 + 3-8 5 27.2 5 38.2 - ii.o 5 32-9 5 44-2 - 1 1.3 5 39-9 5 46.S - 6.9 6 20.6 5 47.1 + 33.5 6 12.3 5 39.1 +33.2 5 51-6 ' 5 34-0 + 17-6 5 28.3 5 38.6 - 10.3 4 34-6 , 4 37-8 - 3-2 4 21.2 4 19-9 + 1-3 4 24.1 4 19-4 + 4-7 4 134 4 I3-0 + 0.4 4 14-7 4 12.3 + 2.4 4 II. I 4 10.5 + 0.6 4 18.3 ,4 174 + 0-9 I I 4 22.2 , 4 27.7 ; - 5.5 4 29.7 4 33.1 - 3.4 4 21.5 4 40.3 - 18.8 t 4 18.8 4 51.8 - 33.0 4 58.1 4 51.2 + 6.9 4 51-I 4 58.6 - 7-5 Bracketed number sliows tliat the station U excli led in tlie equations of condition. MAGNETIC SURVEY OF JAPAN FOR THE EPOCH 1895.0. 73 3CA^. {Continued.) {d, d, W, and I) Redr.ced to 1895.0 and S(^i Levd. Dip e. Horizontal Force IT. T„ till Force I. No. Ob- servfd Calcu- lated Obs.-fal. Ob- sfiveil ^aleir '"-''"'■ ()b- serveil Calcu- lated 01)s.-Cal. c 54 03-1 0 ' 54 07.4 - 4-3 27930 27992 — 62 47576 47764 - 1 88 190 54 15.2 54 29.7 - 14-5 27966 27862 + 104 47871 47974 - 103 191 54 47-5 54 42.7 + 4-S 27760 27809 - 49 48148 48139 + 9 192 55 18.0 55 05.0 + 130 27524 27634 — no 48348 48278 + 70 193 55 28.3 55 22.7 + 5-6 270S9 27477 - 388 47791 48363 - 572 [194] 55 09.1 55 057 + 3-4 27540 27551 — II 48197 4S14S + 49 [195] 54 43-3 54 41.8 + '-5 27691 27713 — 22 47946 47953 - 7 196 54 57.0 54 41-5 + 150 27711 27760 — 49 48253 48031 + 222 197 49 53-4 49 46.7 + 6.7 295S1 29601 : — 20 45915 45840 + 75 198 49 08.1 49 08.4 - 0.3 29737 29712 + 25 45451 45416 + 35 199 49 16.7 49 173 - 0.6 29661 29642 + 19 45464 45446 + 18 200 48 55-7 49 03.8 — 10. 1 29756 29673 + 83 45291 45317 - 26 201 48 44.2 48 43-7 + 0.5 29762 29826 - 64 45126 45217 - 91 202 48 19.0 48 26.1 - 71 29849 29939 - 90 4-1885 451-5 — 240 203 48 39-5 48 47.1 - 7-6 29821 29848 - 27 45146 45301 - 155 204 49 50.0 49 507 - 0.7 29469 29466 + 3 4 5 688 45693 - 5 205 50 24-5 50 24.4 + 0.1 29257 29259 ! — 2 45907 45908 — I 206 50 58.0 51 02.0 - 4.0 29328 29034 + 294 46569 46169 + 400 207 51 311 51 40.5 - 9-4 29017 28833 + 184 46632 46495 + 137 [208] SI 03.2 51 23.8 — 20.6 29171 28961 4- 210 46407 46417 — 10 209 51 24.7 51 37-6 - 12.9 29047 28921 -4- 126 46570 46588 - 18 210 74 A. TANAKADATE. TA.BI.E Obscrvod and Calculate« 1 Values of IMagnetic Elements 211 Yiiinagata 212 ' Sinzyö 213 I Sîikata [214] Atnmi No. Statif 215 216 21S 219 220 221 Murakami O^rnni in Uzcn... Tngawa Wakamatn Tazima Tadami ... Nikk5 Sukagawa. Nisi-nasnno 24 I Utnnomiya Koga Î25 227 228 229 230 2^1 HatimaninOiiii Kyoto Sasavama Miyatii Obania . . Ileiglil Year. Latitude. Longitude in km. ' Sak cai 0.61 0.20 0.12 0.02 0.05 0.04 0.25 o.oo 0.00 0.00 0.16 ' 1895.59 38 16.5 c.io 1S95.60 38 46.2 0.00 , 1895.61 ; 38 54.5 o.co I 1S95.61 38 37.1 I I 0.00 ' 1895.61 i 38 12.0 o.io I 1895.62 38 04.9 0.08 I 1895.63 37 39.5! 0.22 1 1895.64 37 29.5 ! 0.56 : 1895.64 1 37 11-5 1895.65 57 20.5 1895.66 3Ô 44.3 1895.6Ô 37 15.5 1895.66 1895.67 1895.67 1896.50 1896.51 1896.52 36 53-0 36 334! 36 11.7I 35 07.S 35 OI-2 35 04.2 1896.53 35 31.6 1893.53 35 30.8 I 1896.55 34 34-9 ^o 21.0 40 18.0 39 48.0 39 350 39 28.5 39 46.5 39 24.0 39 57.0 39 46.5 39 19.0 39 37.5 40 2 1 .0 39 58.5 39 54.0 39 41-8 36 04.3 35 47-8 35 14-0 35 13.0 35 44-5 35 28.0 Declination 5. Ob- Calcni- served ! luted 4 44.0 5 01.4 5 09.6 5 10.2 5 12.0 5 18.2 ... ! s 15.7 5 10.9 5 09.9 - 174 - 0.6 - 6.2 + i.o 4 59-5 5 04.7 : - 5-2 5 08.5 5 01.5 I + 7-0 4 48.3 4 52.8 Î - 4-5 4 41.5 ! 4 49-7 4 40.7 I 4 56.9 4 26.2 4 43-5 4 51.S 4 44.5 4 58.8 ■ 4 42.3 4 25.6 : 4 37-6 4 29.7 • 4 33-5 4 43-1 4 43.1 4 45-2 4 42.5 4 48.4 4 46.0 4 50-4 4 544 4 56.1 4 518 4 30.4 4 36.1 - 8. — 16.2 - 17-3 + 7-3 + 16.5 - 12.0 - 3-8 0.0 + 2.7 + 2.4 - 4.0 + 4-3 — 5-7 Bracketed number shows that the station is excl ded in the equations of condition. MAGNETIC SURVEY OF JAPAN FOll THE EPOCH 1895.0. 75 IXIA/^. {Continued.) (o, d, H, and I) Keduced to 1895.0 and hjea Level. Dip 0. Horizontal Force H. Total Force I. No. 211 Ob- served Calcu- lated Obs. Cal. Ob- served ^aîed io'-^'^'- Ob- served Calcn- ,., ,, , kited <-*l.s.-Cal. 51° 5^-8 0 51 59-4 - 2^6 2S936 28771' + 165' 46944 46722' 4- 222 52 27.8 52 32.3 - 4-5 2S722 2S587 4- 135 47142 47000 4- 142 212 5^ 45-0 52 44.9 + 0.1 28648 2S566 + 82 4732S 4719I + 137 213 52 24.S 52 27.4 - 2.6 2S924 2S690 \ + 234 47418 47083 4- 335 [214] 52 00.4 52 00.5 - C.I 28931 28S55 + 76 46998 46877 .+- 121 215 51 45-6 51 50-5 - 4-9 2S95S 288S0 + 78 46785 46744 4- 41 216 51 21.S 51 24.9 - 3-1 29046 29062 — 1Ö 46520 46598 - 78 217 51 16.4 51 lO.O + 6.4 29019 29088 — 69 46385 46387 — 2 21S 51 lO.l 50 5i-c> + 1 9. 1 29070 29209 I - 139 46362 46265 4- 97 219 51 05-I 51 04.2 + 0.9 29217 29184 + 33 46513 46444 4- 69 220 50 18.0 50 21.4 - 3-4 29462 293S4 + 78 46123 46055 -f 68 221 50 46.2 50 52-3 - 6.1 29145 29150 - 5 46083 46192 — 109 222 50 28.4 50 28.9 - ^•5 29400 -9:09 + 91 46194 46060 4- 134 223 50 09.1 50 07-3 + 1.8 29532 29433 + 99 46089 45907 -i- 182 224 49 48.4 49 44.0 + 4-4 29455 29575 - 120 45639 45757 - 118 225 48 52.8 48 55-4 - 2.6 30191 30217 - 26 45908 45988 - 80 226 48 47.7 4S 49.8 - 2.1 30256 30278 - 22 45929 45995 - 66 227 4^ 57-3 48 58.0 - "■'•7 30239 3°3^- - 73 46050 46173 - 123 228 49 28.2 •19 30.6 - 2-4 30159 30156 ■\- 3 40409 46442 33 229 49 22.0 -19 25.2 - 3-2 30074 301 13 - 39 461S2 46291 — IC9 i 230 4S 36.9 4S 21.1 + 15.8 303S7 30457 - 70 45963 -15831 4- 132 -3^ 76 A. ÏANAKADAÏE. TABULE Observed and Calculated Value« of Magnetic Elements No. Stilt iun. Declination S. Height in km. Year. Latilude. Longitude! 01)- servcM Calcu- lated Obs. -Cal. 232 Ikuno 233 ) Toycuka 234 \ Totturi 235 Hasizu 236 Tiivama I 237 Okayami 23S Akr. 239 Ak;isi 240 Xara 241 Kamiiti 242 j :\Iyr,zi 243 I "Wakayama 244 Suaiotu 245 Minabe [246], Tikatuyu 247 Flongû 24*^ Kusiiuoto 249 Arinia j 250 Naga.slnia 251 :Matu.saka 1 252 Miliara Bracketcil number 0.25 i 1S96.55 35 10.3 134 48.0 o.co 1S96.56 35 32.6: 134 49-3 0.00 1896.56 35 -9-7 134 i4-î^ coo 1S96.57 35 304 ^33 54-0 0.09 1896.58 35 04.0 134 01.3 0.00 1896.58 34 404 ^33 55-^ o.co 1896.59 34 454 1 ^34 23.8 0.00 ! 1896.59 34 39-2 1 135 oo-o 0.06 1896.60 34 40.9 135 51-0 0.15 1896.61 34 23.4 135 52.0 0.00 1896.61 34 17.0 135 3~-3 0.00 1896.61 34 13-6, 135 11-3 0.00 1896.62 34 20.7 ! 134 53-5 0.00 1896.62 j3 45-6^ 135 -°-3 I 0.4S 1S96.63 i 33 48.9 135 36.9 o.io , 1896.64 33 49.1 135 47-5 0.00 1896.64 33 28.2 : 135 47-0 I 0.00 I 1896.65 33 52.2' 136 05.5 0.00 I 1896.66 34 12.2 136 20.5 0.00 I 1896.67 j34 34.3' 136 32.5 0.00 : 1896.50 34 24.3 J 133 05.3 I I 4 50-3 4 49-6 j + 0.7 4 59-9 ! 4 56-3 ) + 3-6 5 044 4 574 5 01.0 4 58.6 + 2.4 + 7-0 4 464 4 50.1 4 39-1 ' 4 43-0 4 39-2 4 43-3 - 4-i 4 35-S j 4 39-3 ! - 3-5 4 27.6 4 3f^-i I - ^-5 4 26.9 4 3^.7 - 3-« 4 26.4 4 30.3 - 3-9 4 29.0 4 30.7 - 1-7 4 30.7 4 34-0 — 3-3 4 157 4 4 21.5 21.3 - 5-« 4 18.8 4 20.6 - 1.8 4 10.4 4 14.2 - 3-8 4 15-9 4 20.1 - 4-2 4 21.9 4 24.8 - 2.9 4 2 5.8 4 30.4 - 6.6 4 39-2 , 4 39-5 I - shows that the station is excluded in the equations of condition. 31AGNETIC SÜEVEY OF JAPAN FOR THE EPOCH 1895.0. 77 _XLA^. {Continued.) (o 0, 1 I, ^ nul J ) Reduced tu 1895.0 and fSea Level. Di p *'■ Horizontal Force H. To al Force I. No. Ob served Calcu- lateil Ol.s.-Cal. O).- sorvc'l Calcu- lated Obs.-Cal. Ob- served Calcu- lated Obs.-Cal. 0 49 09!^ 49' 08.9 + 0^3 30165' 30318 - 153 46121 46350 - 229 232 49 30.3 49 35-2 - 4-9 30187 30188 — 1 46486 46565 - 79 233 49 45-3 49 36.9 + 8.4 30151 ■ 30260 — 109 46670 46703 — 33 234 49 49.1 49 41.0 + 8.1 30204 30291 - 87 46812 46817 - 5 235 49 06.5 49 08.3 - 1.8 30367 30429 - 62 46387 46511 - 124 -3^> 48 39-4 48 40.8 - 1-4 30543 30572 - 29 46237 46302 - 65 -37 4S 41.9 48 42.7 - 0.8 30488 30498 — 10 46190 46219 - 29 238 48 29.0 48 30.1 — i.i 30451 30475 - 24 45940 45993 — 53 -3'i 48 39-3 48 -5-3 + 14-0 30250 30389 - 139 45793 45791 + 2 240 48 034 48 04-3 - 0.9 30448 30486 - 38 45554 45624 - 70 241 47 56.3 47 59-1 - 2.8 30506 30551 - 45 45537 45645 — 108 242 48 C0.6 47 57.8 + -'.8 30531 30601 - 70 45636 45700 - 64 243 48 08.6 48 08.8 — 0.2 30551 30589 - 38 45786 45847 - 61 244 47 24.2 47 22.9 + 1.3 3074- 30743 — I 45420 45404 4- 16 245 47 -5-1 47 24.8 + 0.3 30599 30701 — 102 45222 45368 - m6 [240] 47 -3-5 47 -3-7 — 0.2 30630 30684 - 54 45245 45327 - 62 247 46 56.3 46 58.5 - 2.2 30709 30800 - 91 44977 45141 - Km 248 47 27.5 47 ~5-^ + ^-3 3055-^ 30641 - 89 451^7 45286 - 99 2-49 47 48.4 47 47-3 + i-i 30405 30509 - 104 45267 45409 - 142 250 48 10.2 48 12.2 - 2.0 30319 30368 - 49 45462 45565 - 103 251 48 25.4 48 29.0 - 3-6 30867 30749 4- iiS 46513 46393 + 123 252 78 A. ÏANAKADAÏE. Observed and Calculated Values of Magnetic Elements No. Si at ion. 253 I llirosima 254 Sitat;i 255 Miirtidzuiiii 256 =" - I 25S Ilaçri Yarnagiiti ïuwano ... 59 Awaiiü. [260] 261 262 263 [264] Ilamada Itiki Miyosi. Ai Iiuaili . 265 I Matiie 266 Kurosaka.... [267]! Tôzyô 26S Ilukuvania... (in liiingo) [269] Ilaiualiata.... 270 ; ïakalKisi 273 Usalo. Heislit Year. LatiUule. Longitude, in km. 271 ; Toku.sinia 272 I Wakiniati o.oo 1S96.50 34 23.0 132 27.0 o.oo 1S96.51 33 54.3 1 132 19.5 c.oa 1S96.52 2_i 55.7, 131 58.0 0.04 j 1S96.52 I34 11.7^ 131 29.0 0.16 1S96.53 34 28.0 [ 131 46.5 o.ci I 1S96.54 I 34 25.1 ! 131 22.5 0.00 1896.54 34 22.0 1 130 58.G 4 34-3 4 3^-6 Declination 5. I )lj- I Calcii- »Tved ; luted Obs.-Cal. 4 33-2 4 39-7 - 6.5 4 31.9 4 30-6 : + 1-3 4 33-1 4 31-0 , + 2.1 4 31-9 4 35-9 ; - 40 4 40.3 4 41-3 - i-o 4 33-2 4 40.1 - 6.9 o.oo 1896.56 , 34 53.7 ' 132 05.8 0.28 1896.56 34 49.5 132 25.0 I 0.15 ' 1896.57 34 48.7 132 52.0 0.32 ' 1896.58 35 08.0 132 57.5 0.00 ^ 1896.58 ,35 21.0 1 132 44.5 0.00 I 1896.59 35 28.4 133 04.0 0.09 1896.59 35 ii.o 133 23.8 0.29 ■ 1896.60 34 53.5 133 18.0 0.00 ! 1896.61 34 28.7 133 22.5 : o.oS 1896.61 34 48.;j 133 37.8 0.08 1896.61 34 48.8 133 37.5 i ' I ! ! 0.00 1896.62 34 C4.0 134 35.0 0.05 1896.63 34 05.0 134 1 1.8 0.00 \ 1896.64 1 33 35.0^ 134 23.0 4-3 4 417 4 49-6 j - 7.9 4 42.0 4 48.1 — 6.1 4 56-9 4 47-5 [ + 9-4 4 55-1 4 53-5 + 1.6 4 50.4 4 57-« j - 7-4 4 52.0 4 59.7 - 7.7 4 52-8 4 53.7 - 0.9 4 41.7 4 48.4 - 6.7 4 40.7 4 40-5 + 0.2 4 46-1 4 45-4 4 4(>-3 - 0.9 4 29.4 4 29.9 - 0.5 4 304 4 31-3 - 0-9 4 22.6 4 21.5 j 4- I.I Bracketed number sliuws thai the station is excluded m the ciiuatiuns of condition. MAGNETIC SUKVEY OF JAPAN FOR THE EPOCH 183Ö.O. 79 X"V. (Continuech) (o, ti, H, and I) Reduced, to ISOj.O and Sea Level. Dip 0. lîorizontal Force H. Total Force I. No. f)h- sorved ralcu- lated Ohs. -Cal. Ob- '^erved Calcu- lated Ob-.-Cal. Ob- served Calcu- lated Obs.-Cal. 48 ° 297 48^ 33-5 3.8 30923' 30825 + 98 46663 46573 + 90 253 48 00.8 47 59.6 + 1.2 31009 30997 + 12 46354 46318 + 36 254 48 04.0 48 C4.S - 0.8 31047 31029 + 18 46459 46444 + 15 255 48 24. 1 48 29-3 5-2 31029 30997 4- 32 46737 46769 "~ 32 256 48 46.2 48 46.3 - O.I 30985 30873 + 112 47012 46S45 + 167 257 48 37-4 48 46.9 9-5 3 "45 30936 + 209 47II7 46948 + 169 258 48 40.3 48 47-3 7.0 3 1 109 31002 4- IC7 47109 47055 + 54 259 49 45-4 49 14.4 + 31-0 30354 30693 - 339 46985 4701 1 - 26 [260] 49 19-6 49 06.1 + 13.5 30734 306S1 + 053 47156 46862 + 294 261 49 ii-i 49 00.7 + 10.4 30559 30636 - 77 46754 46708 + 46 262 49 37-2 49 231 + 14.1 30728 30517 + 211 47430 46879 + 551 263 50 04.7 49 40.9 + 23.8 30261 3^467 — 206 47154 47087 + 67 [264] 49 53-2 49 46.6 + 6.6 30212 30390 - 178 46891 47060 — 169 265 49 31-7 49 22.5 + 9.2 30493 30454 + 39 46979 46772 + 207 266 48 53-3 49 02.4 ~ 91 30926 30563 + 363 47034 46624 + 410 [267] 48 32.4 48 317 + 0.7 30750 30694 + 56 46445 46348 + 97 268 48 51-5 48 52.9 1.4 30558 46468 [269] 48 49.2 48 53-7 - 4-5 30670 30556 + "4 46580 46477 + 103 270 47 49-6 47 512 - 1.6 30802 307 1 1 + 91 45879 45768 + III 171 47 52.4 47 55-7 - 3-3 30826 30743 + S3 45957 45882 + 75 272 47 17-3 47 17.6 — 03 30959 30890 + 69 45642 45544 + 98 273 80 A. TANAKADATE. Observed and Calculated Values of Magnetic Elements No. Station. 274 275 276 Nawari Köti Ototi 277 278 Snsaki N:ikiniHira 279 Uwazima 2S0 Wakaiiiiya L2SI] Yahatahania .... 282 Saganoseki 283 284 285 SaikI Oita Matiiyama 286 Kuzii in Tyo 287 Kama „ „ 7S8 Iniabaru 289 293 Kawanoe Marnwarae 291 Takamatn 292 Tonosyö. 293 Zaikôzi 294 Miyazaki Heislit Year. : Latitude. Longitude, in km. 0.00 1S96.65 33 26.0 134 03.0 000 1896.65 .1,5 32.8 133 33.3 0.35 1896.66 1 33 41.0 133 53.0 0.00 1896.67 0.00 1896.67 0.00 i 1896.69 33 24.0^ 133 1 7.8 32 57-7 132 55-0 33 13-2 132 34-5 o.oi ■ 1S96.69 [33 32.0 132 34-5 0.00 ' 1896.70133 27.4 132 25.7 ! 0.00 I 1896.70 33 14.5 13, 53.3 0.00 ! 1896.71 32 56.9 131 52.5 0.00 ; 1896.72 J 33 15.0 131 36.0 Declination 5. Ob- Caloii served lated Obs.-f'al. 4 19.6 4 19.5 + O.I 4 23.6 4 22.6 + I.O 4 24.9 4 24.6 + 0.3 4 20.S 4 20.2 + 0.6 4 1 1.8 4 12.2 — 0.4 4 15.6 4 17.4 — 1.8 I i 4 20.2 4 23.4 - 3.2 4 21.9 4 14-5 4 17-5 ' - 3-0 4 09.4 4 12.0 — 2.6 4 16.7 4 17.7 - 1.0 0.00 i 1896.72133 52.0 132 45.0 4 27-9 4 29.7 0.33 1896.73 133 33-8; 132 58.5 0-53 1896.73 33 394' 132 53.5 o.co 1896.74 34 04.0 133 01.5 o.oo 1 1896.75 34 02.0 133 35.0 0.00 1806.75 1 34 16.9 133 49.0 coo ; 1896.75 34 21.0 134 02.8 0.00 1896.76 34 29.0 134 10.5 O.CO ' 1896.52 Î32 24.2 131 36.8 0.00 { 1896.52 31 55.2 Î 131 25.3 1.8 4 22.7 4 23.7 - 1.0 4 26.7 4 25.5 + 1.2 4 32-8 , 4 33.2 - 0.4 4 303 ' 4 31-8 - 1-5 4 31.0 4 36.0 — 5.0 4 37-5 4 36.7 + 0.8 4 3S.6 4 38.8 — 0.2 4 01.2 4 01. 1 + 0.1 3 59-0 3 51-5 + 7-5 Bracketed number shows that the station is exckided in the equations of condition. MAGNETIC SURVF.Y OF JAPAN FOR THE EPOCH 189Ô.0. ongi- tude. tilde. North Conipt. X Ob- Calcu- sorveil lilted West Cdiiipt. Y Ob- Calcu- scrvcd lilted I" Tok ju. 2 ! Hatiùzi [j] .Sanihasi [4] Kr.hu 5 Uiuinukuti 6 U.suta [7] ]\(Hiiuru ^ .Aliyota 9 j Kanijzawa [lo] ' Kutukake Ueda Kaiuisuwa '^ Matuuiulu, Oiiiati Kuruaia ... i6 Itoigawa... •4 [15] 17 Takata ... iS 19 20 21 yekiyaiua. Nagano ... liyama ïôkaiiiati 0.02 0.02 O.II 0.31 0.26 1.07 0.74 0.67 0.80 0.97 0.99 0.43 0.71 I 0.09 i 0.69 C.60 o.co j o.co 0.56 0.38 0.31 0.16 1893-96 1896.50 1893-51) 1895.48/ 1893-52 1893-52 189353 1893-54 j •893-54 1 1893-54 I I 1893-55 i I I 1893-55 ! 1893.56 1893.56 1893-57 1893-58 1893-58 1893-59) 1893-77) 1893-59 1893.60 1893.60 1893.61 1893.62 35 42.0, 35 41-0 35 40.0 35 36.4 35 39-5 35 59-0 36 II.O 36 19-7 36 19-5 36 21.7 36 20.8 36 24.0 36 02.3 30 14.0 36 28.0 36 48.0 37 02.5 37 06.8 36 56.5 36 39-8 36 5^-3 37 C9.0 139 46.0 139 45.0 139 20.0 138 58.8 138 34-5 138 2-].:, 138 28.1 138 26.0 138 30.5 138 38.3 138 33-0 138 15.6 138 07.7 137 59-0 137 49-5 137 510 137 5--0 138 16.0 138 13-5 138 12.0 138 22.2 138 44.0 29672 29726 29671 29100 28794 29750 29845 29659 29666 29695 29738 29744 29633 ^9559 29399 , 29507 -9555 29618 29756 29767 29499 -95'^ 3 29662 29128 29241 2922S 29232 29247 29504 29482 29494 29492 ^9635 29573 29498 29372 29280 29226 29294 29399 293 1 1 29235 : 29183 2287 I 2285 2319 2284 2374 2592 2463 2225 2442 2344 2384 2433 2456 2467 ! 2476 2435 I 2470 2448 I 2464 2644 2469 2498 2513 -465 I 2376 2500 -555 I -541 2473 ; 2577 2620 2659 2562 2539 2605 2581 -'565 2534 2620 j 2545 j 2577 ' 2547 Bracketed number shows that the station is exchided in the e<|uations of condition. MAGNETIC SURVEY OF JAPAN FOR THE EPOCH 189Ô.O. 87 XVI. X, y, Z, and Intensity and Direction of Disturl)ing Forces. Upward Conipt. Z Norlli Coiiipt. AX AVest Conipt. AY I'pward Conipt. AZ '1 1^ + + Azimuth N-W-SKN Altitude. No. Ol)sorvo(l raUuhtt.Hl ohs.-Cal. Obs.-Cal. Ol.s.-Cal. <1 -34329 -34414' + 13 + 2' + 85 T 13 86 0 9 + 0 81 1,1 -34299 - 34400 + 60 + 35 + lOI 69 123 30 + 56 il, - 34290 -34467 - 24 + 53 + 177 58 186 114 + 72 2 -34535 -34477 - 63S + 248 - 58 685 687 159 - 5 [3] -34714 -34615 - 950 + 79 - 99 953 958 •75 - 6 [4] -34647 -34967 + 117 — 20S + 320 239 399 299 + 53 5 -35424 -35166 + 286 - 14 - 25s 286 385 357 - 42 6 -36320 -35320 - loS - 9 — 1000 loS 1006 1S5 - 84 [7] -35283 -35299 + 51 - 35 + 16 62 , 64 326 + 14 8 -35234 -35306 + 136 - 16 + 72 137 155 353 + 28 9 -34613 -35312 + 699 • •• + [■0] -35634 -35432 + 264 + 146 — 222 302 375 29 - 36 1 1 -35264 -35098 + 132 + 48 - 166 140 217 20 - 50 12 -35279 -35330 - 74 - 124 + 51 144 153 239 + 20 I Î -35626 -35607 + 5 + 14 - 19 15 24 70 - 52 M -35799 -35941 + 290 — 104 + 142 308 339 340 + 25 [•5] -36142 -36183 - 152 + 15 + 41 153 158 174- 4- 15 16 -36145 -36153 + 15 + 78 + 8 79 1 80 79 + 6 '7 -36081 -35989 - 66 — 3 - 92 66 113 183 - 54 18 -35666 -35714 - , 167 + 5 + 48 167 174 178 4- 16 '9 -35901 -35884 _ 64 + 75 - 17 99 100 131 - 10 20 -36163 -36076 + 72 + 30 - 87 78 117 23 — 48 21 * -)- from the horison towanl the zeijith. from the hnrison towiird tlie nadii 88 A. tanakadate. Observed and Calculated Values of IMagnetic Elements No. Htation. 22 [23] [24] 25 [26] 27 Nagaoka Kiisiwazaki Teradoniari. Niigata. Kanio ... Sibata... Ebisn Wasizaki. 30 Aikawa , 31 < )çri . [32] [33] Ozasa Wakasare [34] ] Asama.... 5 Matuida. Takasaki 37 38 Nu mata. KumMgai. 39 Odawara.. [40] Ataiui [41] I Simoda.... 42 ; MatnzTki, Height in km. Lati- tude. Longi- tude. North Compt. X Ob- Caleu- servecl lated 0.03 I 1893.64 37 27.0 I j 0.00 1893.63 I 37 22.5 I I 1893.64 ! 37 38.2 0.0 3 O.IO 0.02 0.00 0.00 0.05 0.10 0.90 1.40 2.45 0.26 O.IO 0.42 0.03 0.00 0.00 0.00 0.00 1893-64) „ -.0 1895.62/! j7 54-Ö 1893-65 1893-66 1893.67 1893.67 1893.68 1893.69 1893.70 1S93.70 1893.70 1893.70 1893-71 1893-72) 1895-493 1893-72 1893-74 1893-75 1893-77 1893.78 37 37-5 37 56.0 38 05.2 38 18.5 38 02.5 37 49-0 j 36 29.6 36 24.6! 36 24.0 1 36 18.5 j 36 19-5! I i 36 39-2 36 09.0 35 15-0 35 05.7 34 40.5 M 45-3 Bracketed number .shows that the station is ex 38 52-2 38 34-3 .38 45-5 39 02.2 39 03.0 39 19-0 38 25.5 38 31-0 38 14.2 38 15-4 38 30.5 38 34-2 38 30.5 38 48.6 39 00.5 39 02.0 39 23.2 39 09.8 39 05.0 38 57.8 38 48.5 West Compt. Y Ob- served Calcu- lated 28892' 29061' 29108 28997 28766 28875 28858 28983 28787 28850 28866 28847 28652 28755 28621 28876 29138 28961 29461 29442 29805 29469 3015 1 29476 29528 29491 29496 29473 29345 29350 29475 29516 30I2I 29856 29265 29916 30123 30072 30061 30053 2649 2766 2782 2812 2570 2589 2600 2606 2573 2583 291 1 2678 2873 2694 2694 268S 2631 2662 2149 2490 1974 2475 1694 2479 2421 2443 2529 2428 2405 2465 2229 2374 241 1 2284 2275 2272 I95I 2228 2305 2252 'ludiil in the equations of con(Ution. MAGNETIC SURVEY OF JAPAN FOR THE EPOCH 1895.0. 89 IXL^V^I. {Continued.) X, Y, Z, and Intensity and Direction of Disturliing Force.«. Upward Z Conipt. North Conipt. AX West Compt. AY Upward Conipt. AZ + "-1 ; + VI + -1 Azimuth X-W-S-E-N Altitude. No. Observed Calculated Obs. -Cal. Obs.-Cal. Obs.-Cal. -1 -36679 -36344 — 169 4- 79' - 335' 187 383 0 155 - 0 61 22 -36S24 -36342 - 482 - ... [23] -36765 -36560 - 2C5 - [24] -36S70 -3676S — 109 + 160 — 102 194 219 124 - 28 25 -37068 -36475 - 125 + 2C9 - 593 244 641 121 - 68 [26] -36622 -36717 - 63 + 229 4- 95 238 256 105 + 22 27 -36934 -37099 + 19 4- 233 4- 165 234 286 85 4- 35 28 — 37C82 -3729S - 103 + 179 4- 217 207 300 120 + 46 29 -37002 -37104 - 255 + 6 4- 102 255 275 179 4- 22 30 -36694 -36870 + 177 - 31 4- 176 I So 252 350 + 44 31 -3634^ -35470 + 19 - 341 - 87S 342 942 273 69 V3A -3559^^ -35372 + 336 - 501 - 226 603 644 304 - 21 {iS\ -38311 — 35375 + 675 - 7S5 - 2936 1035 3113 311 - 71 [34] -35294 -35214 + 37 - 22 - 80 43 91 329 - 62 35 ~ 35433 -351SS + 23 + ICI - 245 104 266 77 ~ 67 36 -35491 -3550S 5 - 60 4- 17 60 63 265 + 16 37 -35193 -34933 - 41 - 145 — 260 151 3' I 254 - 60 38 -34947 -34088 + 265 4- 127 - 859 294 908 26 - 71 39 -33725 -33949 - 651 + 3 : 4- 224 1 651 688 180 + 19 [40] -33394 -33555 + 51 - 277 4- 161 282 324 280 + 30 [41] -33719 -33663 4- 8 : 4- 53 - 56 54 78 81 — 46 42 " + from the liorison toward the zenith. — fruni tlie horisou toward the nadir. 90 A. TANAKADATE. TABLE Observed and Calculated Values of Magnetic Elements Xo. 43 44 [45] [4-3] [47] [4^] [49] [50] [51] [5^] [53] [54] [55] [56] [57] [5"^] [S9] [60] [6.] [62] 63 Station. Height in km. 1 Year. Lati- tude. Longi- tude. North Cunipt. X Ob- I Calcu- served ! lated Iliidisawa (Itu Midono .... Yosida Umagaesi Huzi, East side Syakadake ... „ Sahiokawara near Kinnieisui. „ Sainokavvara near Ginmeisui. ,, Bottom of Crater Muravama Hiromibara „ Down UzLiragoya .. „Up Uzuragoya... Mituike M itu ike Cave... Front of Mituike Cave. Front of Hitoana Itimaiiwa in Hitoana Front of Hitoana (huiya Numazu 0.00 1 1893.79 35 20.8 I 0.00 i 1893. S I 35 15.4 t 1893.82 "•55 * 1^93-51 35 20.0 t '893-81 ' I 0.S4 * 1893.51 35 28.0 f 1803.81 [ 1. 00 * 1893.52 35 25.0 3-73 . 1893-53 35 21.7 3.60 1S9353 35 21.7 3-72 1S93.53 35 21.4^ 3-56 j 1S93.53 35 21.5 j 't 1893.80 1 0.50 j« 1893.53 35 15-0 1 1893.80 I 0.73 1*1893.54 35 21. 1 ! 0.69 1893.54 35 21.0 ! 0.78 ! 1893.54 35 21. 1 0.82 ^ 1893.54 35 22.4 0.82 1893.54 35 22.4 0.S2 1893.54 35 22.4 0.69 j 1893.55 35 21.5 0-69 ! 1893-55 35 21.5 0.69 1 1S9355 35 21.5 't 1^93-79 o.ii ,* 1893.55 35 13.5 t 1893.82 0.00 ,* 1893.55 35 05-0 39 29.3 39 42.5 38 54-0 38 48.0 38 47-0 38 44-0 38 43-8 38 43-9 38 43-9 38 40.0 38 36.7 38 36.3 38 37-2 38 35-9 38 35-9 38 35-9 38 35-5 3^ 35-5 38 35-5 38 38.0 38 52-5 29529 j 29802 29748 1 29822 29131 I 29841 29643 28737 30550 29711 29799 29818 29838 29841 29843 29842 29886 ... 29853 29851 29845 29845 29845 29851 29851 ... i 29851 30187 1 29896 30018 , 29932 West Compt. Y Ob- Calcu- served lated 2358 2232 22^2 1812 1650 1710 2324 2268 2236 2317 2342 2337 2334 2334 2334 2334 2326 2343 2343 2342 2346 2346 2346 2345 2345 2345 2326 2287 Bracketed number shows that the station is e t Ejiocli for llie observation of S. * Epoch •luded in the equations of condition. )T tlie observations of 0 and H. MAGNETIC SL'RVEY OF JAPAN FOE THE EPOCH 1 8l)fJ.O, 91 _^^ \/ X. {Continued.) X, Y, Z, and Intensity and Direction of Disturbing Forces. Upward Compt. Z Observed I Cak-ulated Nortli Compt. AX OI)S.-Cal. West Compt. AY Upward Compt. AZ Obs.-Cal. Obs. -Cal. Azimutli K-W-S-EN Alt itiide. N,,. - 0 2 43 + 63 44 - 29 [45] - 7 [46] - 27 [47] - [4S] - [49] - [50] - [51] - 44 [53] - 21 [53] + [54] - ... [55] + [56] + [57] + ... [5S] + [59] + [60] + [61] - 28 [62] + 43 63 -34130 -34II9 -33S44 3989 -34618 - 34222 — 3444S I —34376 — 34883 I —34328 -44174 I -342SI -38496 -342S6 -4I4I4 ' -34283 -34330 I -34281 -35109 -34187 -34552 i -34300 -33972 -34300 -35257 I -34297 -28614 I -34324 ! -33516 -34324 -31949 -30794 — 27671 -28695 -34322 -33891 -34324 -343" -343" -343" -34169 -3397S 273 74 710 156 108 1 + 664 - 141 + 291 + 86 + 90' - II - 4 + 145 - 65 - 396 - 530 72 + 43 - 555 9893 4210 - 7134 - 49 - 676 - 922 - 633 - 252 + 328 960 + 5710 ... + 808 + 2375 + 3517 + 6640 + 5616 - 16 - 153 + 37 + 87 287 74 713 552 1082 948 649 291 94 288 163 816 557 1216 696 329 128 162 183 185 254 178 257 357 + from the horison toward tlie zenith. — 1V> m the horison toward the nadir. 92 A. TANAKADATE. TABT.TÏ; Observed and Calculated Values of iMametic Elements No. Station. 64 I Simizu... 65 I Nisinoto. Okaz;iki . Kôwa .... Nariinii ., Nagoya .. 69 70 71 72 73 74 75 76 77 78 79 80 81 [82] 83 84 Maegasu ... Yokkaiti.... Karaevama. Til Kannyasiro. Toba Katikuwa .. Kiyosu , Gihu Nakutugawa lida Matiiô Hukiisiina Nomiigi ... Takavama Height in km. Year. Lati- ] L'lngi- tude. I tude. t 0.00 - t 0.14 " t 0.05 * ;t 0.00 J * t 0.00 ; * 0.09 t 0.00 , * 0.05 0.15 0.30 0-53 0.53 0.78 1. 16 0.56 '3-72) 13-50^ )6.6s3 893-79 893-56 893-78 S93.56 89^77 893-57 893-74 893-5« 893-75 893-58 893.71) -93-58 896.76) 8^3-71 893-59 893.72 893-59 893-72; 89, S96. 893-73 893-60 893-73 893.60 893-73 893-61 893-76 893-61 ^93 75 «93-61 «9^.68 S93-62 89377 893-63 «95-78 «93-64 «93-64 «9J.65 «93-65 «93-^6 35 00-5 138 30-0 35 02.0 137 50.0 34 56-5 137 08.0 34 46.0' 136 55.5 35 05.0 136 58.0 35 10.5 136 56.0 35 06.0 136 44.0 1 34 58.5 136 37-5 34 52.0 136 28.0 34 43-0 136 31-0 34 30-0 136 45-0 I 34 29-0 136 50.0 35 13.0 136 58.0 35 12.0 136 51.0 35 25-5 , 136 46-0 35 29.0 137 32.0 35 31-0 137 50-0 35 29.0 137 52.0 i 35 50.0 137 42.0 36 02.0' 137 35.0 36 oS.o^ 137 16.5 North Compt. X Ob- Calcu- served ! lated 30072 29960 30016 30158 30033 30084 30073 30108 30102 301 13 30252 30321 29991 2C 29961 29802 29764 29744 29503 29831 29712 299S2 30017 30099 30176 30061 30031 30073 30126 30176 30225 30284 30282 30014 30028 29954 29S77 29844 29853 29739 29673 29660 West Coinpt. Y Ob- served Calcu- lated 2203 2309 2305 2362 2378 2398 2421 2389 2449 2428 2476 2441 2460 2444 2429 2434 2399 2430 2355 2406 2369 2365 235S 2357 24S8 2445 2455 2449 2487 2484 2462 2441 2379 2423 2408 2417 2559 2472 2580 2505 2528 2539 Bracketed number shows iha t Epoch for the observation llie station is excluded in the eiiu.aiuiis of condition, of 0. * Kpocli for tiie observations of 0 and H. MAGNETIC SURVP:Y OF JAPAN FOR THE EPOCH 1895.0. _5C"V^I. [Continued.) X, Y, Z, and Intensity and Direction of Disturl)ing Forces. 93 Upward Cotiipt. North Conipt. \Vest > Coiiipt. ITpward Conipt. J ^ AX AY AZ + ! "-< 1 + >< Azimuth N-W-S-K-N Altitude. No. Obseivoil Calculated Obs. -Cal. 01 IS. -Cal. s.-CaI. (ii,s.-Cal. Obs -Cul. -35020' -35062' + 18 - 4 4- T 42 I S 46 0 347 4- 67' ^5 -3497S -35072 + 73 + 14 4- 94 74 120 II 4- 52 S6 -35028 -35103 - 39 + 51 4- 75 64 99 127 4- 50 87 -347^!:5 - 34878 — 16 + 10 4- 90 19 92 148 4- 78 8S -35196 -35^24 + 112 - 27 4- 2^ "5 119 346 4- 14 89 -35478 -35430 + 394 + 6 - 48 394 397 I — 7 90 -35552 - 35449 + 15 - 43 — 103 46 113 289 - 66 91 : -35762 -35812 - 96 + I 4- 50 96 108 179 4- 28 92 ; -36267 -36007 - 47 - 13 260 49 265 195 — 79 92, . — 36660 -36434 + 69 0 226 69 236 0 - 73 94 -36764 -36787 - 144 - 34 4- -3 148 150 193 4- 9 95 ■ -35971 -35963 - -'45 4- 6 - 8 245 ^45 179 — 2 96 -35521 -35756 + 138 - 15 + -35 139 273 354 4- 59 97 -359^^1 - 36089 - 16 4- 44 4- 108 47 118 no 4- 66 98 — 40696 -40S58 - 369 4- I 4- 162 369 403 I So 4- 24 99 : -40839 -40942 + 161 - 130 4- 103 207 231 321 4- 26 100 -41122 — 41262 + >i — Ill + 140 112 179 276 4- 51 lOI -41051 -41353 — 1 10 + 62 4- 302 126 327 151 4- 68 102 -41567 -41738 + 294 - 147 4- 171 y-9 371 333 4- 27 [103] -41938 -41674 4- 7 - 716 - 264 lie 763 271 - 20 [104] -41481 -41402 - 8 4- 9 79 12 80 132 — Si L105I * 4- iVuiu Uie iiuiisou toward the lieiiilli. (Vom the liorison toward tlie nadir. 9C) A. TANAKADATE. XABILE Observed and Calculated Values df Maonetic Elements No. Station. Height in km. Year. Lati- tude. Longi- tude. Nurtli Com I it. X ()))- Calcii- served ; latcd West C'oiupt. Y Ob- served Calcu- lated Otaru io6 , Mvôkenzan. 107 Sapporo [loS] Iwamizawa. 109 Soratipt no Tip-Yabusi. Ill Asahikawa . [112] Ohotukawa... [113] Porokamuikotan 114 "5 116 117 Masike Sirasitoinari Hören Tesio [118] Pösinai-pitari.. Okurumatoma- [119] nai [120] Nayoropt . [121] Nuppamamoi... [122] Wakasakanai... Wakkanai 124 oya [125] Sarubutu. [126] Esasi 0.04 0.00 0.00 0.00 0.21 0.00 0.70 0.00 0.00 0.00 0.00 0.04 0.08 o.oi 0.00 0.00 1894.62 ; 43 1 1-9 141 00.6 1894.55 43 04.8 J 141 21.0 1894.56 43 12.9 141 45.0 1894.56 43 34-o] 141 547 1894.57 , 43 26.5 142 17.2 1894.58 ' 43 46.5 142 20.2 26759 26342 26613 26647 o.io , 1894.59 ; 43 43-2 141 57-0 1S94.60 44 00.0 142 06.0 1894.64 43 51-3, 141 31-8 1894.64 1894.65 1894.66 O.CO ! 1894.67 26362 I 26571 26439 2641 I 26420 i 26449 26255 26302 ... 26343 26284 26214 26^66 26;o2 44 1S.7 44 34-6 44 53-3 141 39.0 141 46.7 141 44.1 26079 25982 25761 26097 25974 25837 1894.68 1894.69 1894.70 1894.70 1894.71 44 50.2 142 03.7 25978 25845 0.00 I 1894.71 0.00 I 1894.72 coo j 1S94.73 44 36.0 I 44 23.4^ 44 54-3 45 06.7 45 24.0 45 29.4 45 16.7 44 57-0 142 17.8 142 27.2 141 59.0 141 37-0 141 39.0 141 52.7 142 14.0 142 34-9 25926 26018 25600 25585 2554^' 24992 25940 26028 25818 25742 25612 25560 25640 25773 2952 2897 2851 I 2849 2518 : 2812 2702 2819 2569 2764 2915 I 2782 I ... I 2825 2855 : 2828 2842 2885 2954 2896 2495 3224 ^128 3066 2986 3263 3091 2903 2037 I 2907 2932 2890 2845 281 1 2904 2961 2975 2954 2897 2832 Bracketed number sliow.s that the station is exduded in the eiiuaticns of condition. MAGNETIC SURVEY OF JAPAN FOR THE EPOCH 1895.0. 97 _5C V^X. {Continued.) X, Y, Z, jiiid Intensity and Direction of Disturbing Forces. Upward Compt. Z North Compt. AX West Compt. AY Upward Compt. AZ 4- \U «a IN < + I<1 1 + y, < Azimuth. N-\VS-E-N Altitude. No. Observed Ciilcuhitod 01>s.-Cal. Obs.-Cal. Olis. -Cal. -41465 -41401' + 146 ' V + 55' - 64 156 169 0 21 — 22° 106 — 41050 -4I183 - 305 4- 2 4- 153 305 341 I So 4- 27 107 -41 163 -41 189 — 209 - 294 4- 26 361 362 235 4- 4 [>oS] -41510 — 4146S + 28 - 117 - 42 120 127 283 - 19 109 -41292 -41 241 29 - 195 - 51 197 204 262 - 15 no -41484 -41536 - 47 + 133 4- 52 141 150 109 4- 20 III -4icS66 — 4160I - 265 ... - [M2] -4^443 -41817 4- 70 + 27 - 631 75 635 21 - 83 [■•3] -4175''^ — 41861 4- 64 - 43 4- 103 77 129 326 4- 53 114 -4^435 -42253 - iS 4- 51 - 1S2 54 190 109 - 73 >i5 -42526 -42459 + S 70 - 67 70 97 277 - 44 116 -4283S -42764 - 76 - 36 - 74 84 112 205 - 41 117 -42962 -42604 4- 133 - 395 - 358 417 549 2S9 - 41 [118] -42434 -423II - 14 4- 379 123 379 399 92 - 18 [119] — 42264 — 42069 — 10 4- 317 195 317 372 92 - 32 [.20] -42870 -42695 - 175 - [>2I] -42S95 -43015 4- 120 + ... [122] -43369 , -43273 — 12 4- 91 - 96 92 133 98 - 46 •23 -43251 ' -43274 + 25 4- 32 4- 23 41 47 52 4- 29 124 -42871 -42955 - 94 4- 366 4- 84 378 387 104 + 13 [125] -42999 -42541 - 781 4- 259 - 458 823 942 162 — 29 [126] * + from the horisou toward the zenith. from the horison toward the nadir. 98 A. TANAKADATE. TABLE Observed and Calculated Values oi Magnetic Elenients No. Station. Height in km. Year. Lati- tude. Longi- tude. North Compt. | "West < 'onipt X Ob- Caleii- Ob- Calcu- servecl lated served ; lated Y 127 j Foronai.. 128 Monbetu. [129] Y'ûbetu.. 130 131 [132] Nogami Ainonai , Abasiri . 133 Syari. 134 135 Kausu. Sibetu. 131 Hakodate. 137 ! Mori 13*^ Setana 139 j Kutö 140 Esasi. 141 Hnkuyama.... (in Osinia) 142 Siriuti 143 Tiribetu , [144] Tomakomai. 145 146 Sarupt Osyatinai. [147] Nohuka. 0.00 0.00 0.00 0.00 O.CXD 0.00 0.00 1894.73 ' 44 40-0, 142 52.9 1894.74 0.00 j 1894.74 44 21.7 44 14.0 o.io 1S94.75 \ 44 02.0 0.20 j 1894.75 0.00 I 1894.76 43 48.7 143 21.0 143 37-1 143 30.0 143 48.2 44 01.2 144 16.6 0.00, 1S94.76 43 54.9 j 144 39-6 0.00 I 1894.78 ] 44 01.4 145 12.0 0.00 j 1894.79 0.00 1894.50 1894.51 1894.53 0.00 1894.54 0.00 I 1894.55 0.00 ; 1894.55 43 39-1 145 08.5 41 46.5 140 43.5 42 07.0 140 34.5 42 26.9 139 51.0 42 13.6 139 49.5 I 41 52.5 140 09.0 41 26.0 140 09.0 1894.56 41 36.3 140 25.5 1S94.58 I 42 20.8 141 00.0 1894.58 42 36-5 141 36.0 0.00 j 1894.59 I 42 30-4 142 01.5 0.10 1894.60 0.00 1894.61 42 41.2 j 142 13.5 42 19.4 142 48.0 26033' 25888 26088 26037 26055 26241 26146 26261 26234 26594 26130 26098 26x66 26285 26106 26077 26270 27317 27231 27048 27096 2724X 26996 27147 27091 27II6 27221 27624 27405 27331 27319 26664 26977 26820 26837 26837 26862 26792 26777 26943 26909 T 2817 2745 2557 2268 T 2776 2693 2648 2740 2650 2671 ' 2593 2195 2542 2480 2408 2317 ; 2390 2759 2813 2688 2S58 2906 2961 3061 2945 2910 2883 28 1 4 2845 2645 2831 2868 2S3I 2395 2783 2829 2724 2744 2714 2904 2612 Bracketed number shows that the station is excluded in the e °-°^ , 1895.49 ^^ '5.S 140 52.0 0.00 1895.49 38 31.5 141 04.0 27038 26984 27008 27020 26996 26914 26841 26794 26672 j 26649 26616 , 26590 26616 I 26641 26496 ] 26467 Ob- .served 26897 26565 26351 26732 26605 26438 1895.50 j 38 44.0 141 06.0 1595.51 j 39 07.6 141 05.0 1895-51 39 25.0 141 06.5 1595.51 I 39 42.5 141 07.5 1895.52 I 40 03.3 141 16.5 26453 26301 2647- 26539 25519 ' 26398 28505 ■ 2S640 28705 I 2852S 28062 : 28445 28276 28291 28065 28176 i 28135 28058 27937 2791 I 2885 2650 2509 2519 2710 2839 2538 2645 2819 2361 2635 2447 2585 I82I 2547 2565 ('aleu- hited 2598 2526 2543 2566 2634 2668 2583 2580 252S 2487 2444 2492 2390 2298 2465 2633 2470 2488 2576 I 252S 2697 I 2551 2730 I 2582 2S42 j 2598 Bracketed number shows that the station is excluded in the equations of con.lition. MAGNETIC SURVEY OF JAPAN FOR THE EPOCH 1895.0. 101 _X! \/ I. (Continued.) X, Y, Z, and Intensity and Direction of Disturbing Forces. I'pward Conipt. Z f>b.serv('(l Calculated North Coiiipt. AX West Compt. AY Olis.-Cal. Obs.-Cal. Upwaril Compt. AZ Obs.-Cal. Azimuth 1 N-W-SK-X Altitude. No. ■400S4 -39907 -397" I -396S4 -4C029 I -39904 -40288 ; —40157 -40597 -40564 -4-713 ' -40746 -4032S \ -40457 I -40545 I -40746 -40517 -40186 -40550 -40314 -40234 , -40520 -40582 -40843 -41409 -40250 -40153 -40347 -36571 ' -36688 57100 57008 57280 -36897 -37089 -37469 ■ 37422 -37744 ■37781 j —38019 ■38018 I -38314 + 54 — 12 + 82 + 287 I - 177 + 124 j - 27 - 34 - 125 + 47 - 47 - 131 + 23 j -f 76 - 33 + 26 + 171 + 33 - 25 + 29 + 165 - 40 - 87 + 152 - 67 - 879 - 45 ! + 129 + 65 + 291 - 126 + 191 - 45 + 195 + 201 - 331 - 236 + 2S6 + 261 - 1159 477 + 194 - 135 I + 82 + 117 + 177 ; + 163 - 203 - 383 ! + 77 ' + 81 - 15 + 48 + 1S9 - Ill + 146 + 322 + 77 ! + 148 I + 23S + 26 + 244 j + 296 292 341' 125 127 89 153 6Ö 147 79 86 173 176 51 139 71 213 335 471 132 271 210 355 159 305 206 1177 I GOO 10 1 9 158 197 241 315 391 399 50 190 183 371 167 291 245 384 79 96 338 315 73 81 241 66 60 252 115 344 109 209 149 43 169 107 127 63 84 - 55 - 63 - -3 + II + 68 + 71 - 45 - 61 + 54 + 59 - 80 + II + 37 — 40 U'3 + 12 164 + 75 165 + 60 166 + 55 167 + 50 [,68] [148] 149 150 151 152 153 154 155 [156] 157 [158] [159] [160] [161] 162 * 4- from tlie hoiison toward the zenitli. - from the liorison toward the natlir. 102 A. TANAKADATE. Observed and Calculated Values of Magnetic Elements No. Station. Height in km. Year. Lati- tude. Longi- tude. Nortli C'onipt. X Oh- Calcu- servod i lated West C'oinpt. Y Ob- I Caleii- served i lated [169] 170 [171] Hatinohe. Kominatotaira. _(iu Sameura) Ono .... 172 Kuzi, Kikutyu. [173] 174 Akka Anazawa. [175] Iwaizurai [176] [177] 17S 179 I So iSi [182] 1S3 1 84 Miyako Oguni,Rikutyü Tôno Kamaisi Kesenuunia Isinoniaki . Ikusazawa . Simoinnai . Y'okote .... [185]: Kakudate, [186] Kariwano , 1S7 1S8 1 89 Akita ... Honzyü Nosiro.. 0.04 0.00 0.20 0.00 0.10 0-35 0.08 0.00 O.IO 0.27 0.00 0.00 0.00 0.40 0.18 0.06 0.04 0.03 1895.60 1895-53 1895-53 40 31.0 141 31-3 40 32.3 141 34-3 40 15.2 141 37-8 1895.54 40 11.6J141 47.8 1895-54 ! 39 59-3 141 44-0 1895-55 ' 39 52.5 I 141 41-3 1895-55 39 51-6 141 47-6 1 I 1S95-55 39 38.2,141 58-3 1895-56 ' 39 31-3, 141 41-0 1S95.56 j 39 18.2 ' 141 31.2 1895-57 39 16.1 141 54-^ 1895.58 38 53.5 141 35-3 1895-59 : 38 25.2 141 iS.o ! 1895.60 ' 38 5 I.I ■ 140 37-7 1895.61 39 02.3 140 25.8 1S95.61 39 19.0^ 140 31.5 1895.61 * 39 36.6 140 33-0 1895.61 39 32.2 140 21.6 coo i 1S95.62 39 42.6 140 07.5 0.00 1895.62 ; 39 22.0 140 01.5 I . ! I 0.00 ! 1895.63 40 II. 5 140 02.5 27573 ; 27702 28044 27816 27926 27833 ... j 27919 28063 ' 27967 2796S 28041 28050 ... 2810S 28102 28202 28248 28200 28302 28361 28633 28559 ... 2S422 28060 28359 2S296 2S244 28145 28126 ... 28165 28174 ' 28I0S 28150 28251 27788 , 27919 ... ' 2613 2361 \ 2605 2123 ; 2576 2465 , 2551 2539 2292 i 2534 2758 2490 2649 2520 2477 2500 2629 2498 ! 22C9 2450 2458 ; 2449 2433 2551 2590 2679 2609 2276 ^ 2635 ... I 2647 2646 2688 2576 j 2665 I 2830 Î 2735 Bracketed number «hows that the station is e.xcUuled in the equations of condition. MAGNETIC SURVEY OF JAPAN FOR THE EPOCH 1895.0. 103 ]5CA/^X. {Continued.) X, Y, 7j, and Intensity and Direction of DistnrLing Forces. Upward Compt. Z Ncrth Compt. AX West Compt. AY Upward Compt. AZ 1^ + + '+ X <1 Azimuth N-W-S-EN * Altitude. No. Obsevvoil ! Ciilcuhited Ohs .-Cal. Obs -Cal. Obs.-Cal. -3S475' -38695' Y T Y + 220 '' Y 0 + 0 [169] -3S536 -3S703 - 129 - 244 + 167 276 323 242 + 31 170 -38653 -38421 + 228 - 453 - 232 507 558 297 - 25 [171] -38624 -38325 + 93 - 86 - 299 127 325 317 - 67 172 -38097 -38145 + 48 ... + [173] -37919 -38049 — 38010 + 96 242 + 130 ... 260 291 292 4- 27 174 [175] -37948 -37760 - 9 + 281 - 188 281 33S 92 - 34 [176] -37350 -37714 ... + 364 + [177] -37663 -37541 - 100 + 131 — 122 165 205 127 - 37 178 -37288 -37427 + 48 - 241 + 139 246 282 281 + 29 179 -36838 -37135 - 59 + 9 + 297 60 303 171 + 79 180 -36480 -36745 + 74 + 57 + 265 93 281 38 + 71 iSi -37758 -37309 ... - 449 ... - [182] -37342 -37537 - 299 + 59 + 195 305 362 169 + 33 183 -37753 -37815 + 52 + 70 + 62 87 107 53 + 35 184 -37936 -38063 + 19 - 359 + 127 360 381 273 + 19 [185] -38120 - 38040 - 80 — [186] -38332 -38270 + 66 — 42 - 62 78 100 328 - 38 187 -37927 -37959 - lOI - 89 + 32 135 1 38 221 + 13 188 -38828 ! -38763 - 131 + 95 - 65 162 174 144 — 22 189 * + from the horison toward the zenith. — from tlie horison toward the nadir. 104 A. TANAKADATE. TA^BI^E Observed and Calculated Values of Maçfnetic Elements No. Station. Heiglit in km. Year. Lati- tude. Longi tilde. North Compt. X Ob- Calcu- served lated AVest Compt. Y Ob- Calcu- served lated 190 191 192 193 [194] [195] 196 197 198 199 200 201 202 203 204 205 206 207 [208] 209 210 Odate .... Hirosaki , Adigasawa. Ippongi . ()ma Tanabu . Makado . Aomori . Hukava. Sakura . Sawara . ïyôsi... Itinomiya . Ma«bara... Kisaratii .. Mito . Ueda .. Namie. Watari Huknsima , Yonezavva ., o.oS 0.06 0.00 0.00 0.00 0.00 o. 10 0.00 0.04 0.03 0.0 1 0.00 0.00 O.CXD 0.03 O.OI 0.00 0.00 0.02 0.07 0.2s 1S95.64 1895.64 1S95.64 1S95.65 1S95.66 1895.66 1S95.67 1S95.67 1895-49 1895.50 1895.51 1895.52 1895-53 1895-53 1895-55 1895-56 1895.56 1895-57 1895-57 1895-59 40 16.0 40 36.4 40 36.8 41 10.2 41 30.0 41 I6.I 4^ 52.7_ 40 49.4 36 ii.S 35 43-3 35 52.5 1S95-51 35 44.0 35 22.4 35 05-8 35 23.2 36 21.9 .36 53-5 37 28.3 38 02.2 37 4S-0 37 55-2 40 32.5 40 285 40 13.3 40 31.3 40 54-5 41 14.0 41 09.0 40 43-5 39 16.5 40 13.5 40 30.0 40 51.0 40 22.5 40 06.0 39 55-5 40 30-0 40 48.0 41 00.0 40 49.5 40 28.5 40 05.0 27797 27839 27630 27390 26923 27379 27546 27585 29487 29651 29574 29675 29680 29769 29737 I 29764 293S3 : 29377 29167 29243 28935 29061 28943 T 27862 27727 27670 27494 27337 27417 275S2 27625 29504 29627 29558 29593 29746 2( 29167 28938 28729 28S57 28812 T 2723 265 S 2684 2717 2993 2977 2827 2642 2360 2257 2276 2191 2739 2780 2783 2770 2713 268S 2730 2389 2244 2235 2182 2203 2187 2178 2180 2239 2233 2245 2292 2293 2322 2229 2365 2182 2444 2526 2450 2457 2509 Bracketed number sho\v^^ tliat llie station is excluded in tlie equations of condition. MAGNETIC SUEVEY OF JAPAN FOR THE EPOCH 1895.0. 105 IXl v^I. {Continued.) X, Y, Z, aud Juteii^^itv and Direction of DistiirLinj; Forces. Upward Compt. Z North Compt. AX West Compt. AY Upward Compt. AZ + -1 + •«1 + Azimutli N-w-s-i:-x Altitude" No. Observed Caleuhilerl Olis -Cal. Obs.-Cal. Obs -Gal. -3S51Ô' -3^^703 - 65 + 25' T 4- 187 Y 70 200 0 159 4- 0 70 190 -38S52 -39054 + 112 - 81 + 202 138 245 324 4- 56 I'M -39341 -39293 - 40 - 96 - 48 104 115 247 - 25 11)2 -39749 -395«S - 104 - 66 - 161 123 203 212 — 53 193 -39372 - 39798 - 414 4- 223 4- 426 470 635 152 4- 42 [194] -39554 - 39487 - 38 + 2O4 - 67 267 275 98 - 14 [195] -39 141 -39135 - 36 4- 139 - 6 144 144 105 - 2 196 -39502 -39195 - 40 - 88 - 307 97 322 246 - 72 197 -35116 -35002 - 17 - 29 - 114 34 119 240 - 73 198 -34372 - 34349 4- 24 4- 13 23 27 36 28 - 40 199 -3445!^ -34448 + 16 4- 41 — 10 44 45 69 - 13 200 -34144 -34252 + 82 4- 9 -1- loS 82 136 6 4- 53 201 -33921 -33984 - 66 + 16 4- 63 68 93 166 4- 43 202 -335^1 -33763 - 91 2 4- 242 91 259 181 4- 69 203 -33S95 -3407S - 27 4- 6 4- 183 28 1S5 167 4- 81 204 -34913 -34924 + 6 - 47 4- II 47 49 277 4- 13 205 -35376 -35376 0 - 29 0 29 29 270 0 206 -36173 -35897 + 305 - 136 - 276 334 433 336 — 40 207 -36503 -36476 + 206 — 262 - 27 333 334 308 - 5 [208] — 36092 -36274 4- 204 4- 76 4- 1S2 218 284 20 4- 40 209 -36402 -36524 4- 131 - 52 + 122 141 1 86 337 4- 41 210 * 4- from the horisou toward the zenith. — from the horison toward tiie nadir. lOG A. TAXAKADATE. TABILE Observed and Calculated Values of Magnetic Elements Station. 211 212 [214] 216 217 21S 219 220 221 222 223 224 225 226 227 228 229 230 231 Yaiiuigata Sinzyo Sakata Atumi Murakami .... Oguni, Uzen. Tiigawa Wakamatu Tazima Tadami.... Nikkü Sukagawa. Xisi-nasuno. Utunomiya.. Hatiiuan, Uini., Kyoto Sasavama Miyatu Obama . . Sakai ... Height in km. 0.16 o.io o.oo 0.00 0.00 0.10 o.oS 0.22 0.56 0.37 0.61 0.25 0.20 0.12 0.02 0.04 0.25 0.00 0.00 0.00 Year. Lati- tude. 1^93-59 38 16.5 1895.60 38 46.2 1595.61 j 38 54.5 1S95.61 1 38 37.1 1S95.61 1S95.62 1S95.63 1S95.64 1895.64 1S95.65 1895.66 1895.66 1895.66 1895.67 1S95.67 1895.50 1896.51 1S96.52 38 12.0 38 04.9 37 39-5 37 29.5 37 "-5 37 20.5 36 44-3 37 15-5 36 530 36 33-4 36 II. 7 35 07.8 35 01.2 35 04.2 1896.53 35 31-6 1895.53 ' 35 30-8 1896.55 j 34 34.9 Longi- tude. 40 21.0 40 iS.o 39 48-0 39 35 o 39 28.5 39 46-5 39 24.0 39 57-0 39 46.5 39 19-0 39 37-5 40 21.0 39 58-5 North Compt. X Ob- Caleii- served lated "West Conipt. Y Ob- Calcu- served lated Ï 2S837 2S606 2S530 28S13 2S848 28929 28917 28973 29120 29374 29040 29289 39 540 2944t 39 41. S 29364 36 04.3 30089 35 47-8 35 14.0 35 13-0 35 44.5 35 28.0 30152 30133 30052 29962 30293 2S661 2S471 2S444 28569 28738 2S767 28950 28983 29105 29075 29284 29050 29210 29337 29481 30115 30176 30207 30045 30005 30359 2388 2583 2596 2613 2520 2603 2431 2378 23S3 2279 2471 2552 2279 2308 2483 2507 2534 2545 2587 2;SS 2519 2576 2640 2631 2598 2556 2546 2475 2459 2517 242a 24 10 2404 2374 2351 24S6 2485 2519 2579 2553 2444 Bracketed number shows that the station is excluded in the equations of condition. M AGXETIC SURVEY OF JAPAN FOR THE EPOCH 1895.0. 107 3C\^I. (Continued.) X, Y, Z, and Intensity and Direction of Disturbing Forces Upward Compt. iS'ortli Compt. West Compt. Upward Compt. 1 Z AX AY AZ + -1 Vf y. Azimuth N-W-S-E-N Altitude. No. Observed Calculatetl Obs.-Cal. Obs.-Cal. Obs.-Cal. Y i Y — 36966 1 — 26S12 + 176 Y - 131 - 154 219 268 0 323 - 0 35 21 1 -37383 -37307 + 135 + 7 - 76 135 155 .3 - 29 212 -37674 ' -37564 + 86 - 44 — no 97 146 333 — 49 213 -37574 , -37332 ... - 242 ... - [214] -37038 -36944 + 75 + 15 - 94 76 121 II - 51 215 -36747 -36755 + Si - 36 + S 89 89 336 + 5 216 — 36338 -36425 — 21 + 57 + 87 61 ic6 no + 55 217 -361S7 -36135 - 66 - 44 - 52 79 95 214 - 33 218 -36116 -35S78 -■ 132 - Si - 23S 155 284 212 — 57 219 — 36190 —36129 1 + 45 - 134 - 61 141 154 289 - 23 220 -35487 -35464 + 90 - 141 - 23 167 169 303 - S 221 1 -35697 1 -35833 — 10 + 61 + 136 62 149 99 + 65 222 -35631 ' -35531 + 79 + 14S — lOO 1 68 195 62 - 31 223 -35384 '; -35229 + 107 - 95 - 155 143 211 318 - 47 224 -34S63 -34915 - 117 - 43 + 52 125 135 200 + 23 225 -34584 -34667 - 26 — 3 + 83 26 87 187 + 73 226 -34555 -34623 - 24 + 22 + 68 33 75 137 + 64 227 -34731 -34830 - 74 + 15 + 99 76 125 169 + 53 2 28 -35274 -35321 + 7 - 34 + 47 35 58 282 + 53 229 -35047 -35158 - 43 + 34 + III 55 124 142 + 64 230 -34486 -34247 - 66 - 56 - 239 87 254 220 — 70 231 * + from the horison toward the zenith. — from the horison toward the nadir. 108 A. TANAKADATE. TABLE Observed and Calculated Values of MaoiiL^tic Elements No. Station. 232 Ikuno ^33 Toyooka. 23 \ Tottori..., 235 236 237 238 239 240 241 242 243 244 Hasizu ... Tuyaiua .. Okavama Ako... Akasi Nara ., Kamiiti , Myözi Wakayama Sumoto... 245 I Minabe... [246] Tikatnyu 247 248 249 250 251 252 Hoiigü .... Kusimoto . Arima .... Nagasima. Matusaka. Mihara.... Pleight in km. I Year. Lati- tnde. Ijongi- tude. 0.25 1S96.55 35 IÜ.3 134 4S.0 0.00 1S96.56 35 32.6 134 49.3 0.00 1896.56 35 29.7 13 J 14.8 0.00 1896.57 35 304 133 54-0 0.09 1896.58 35 o^.o 134 01.3 0.00 1896.58 ' 34 40.4: 133 55-S i 0.00 1S96.59 ' 34 45.4; 134 23.8 o.co 1S96.59 34 39.2 135 00.0 1 0.06 1896.60 34 40.9 135 51.0 0.15 1896.61 1896.61 1896.61 34 23.4, 135 52.0 34 17-0 34 13-6: 135 "• 0.00 1895.62 ! 34 20.7, 134 53.5 O.OD I 1896.62 33 45.6 135 20.3 O.4S 1896.63 33 4S.9 135 36.9 o.io 1896.64 i 33 49.1 135 47.5 j O.OD 1896.64 ' 33 28. 2 135 47.0 O.CO 1896.65 S3 52.2 136 05.5 0.00 1896.66 0.00 1896.67 34 12.2 136 20.5 34 34-3 136 32-5 0.00 1896.50 34 24.3 133 05.3 North Coiiipt. X Ob- Ciilcu- served luted 3^057 3C072 3ÛO33 300SS 30262 30442 30388 3^353 30158 30356 30414 3043S 30456 30657 30542 30628 30467 30317 30^30 30210 3-076 30147 30177 30321 30469 30395 30375 30291 30392 30457 30506 30492 30654 306 1 2 .30596 30716 30553 30419 30274 33765 30647 West (.'oiujit. Y Ol)- I Calcu- ieived I lated 2544 : 2551 2630 2599 2666 2615 2641 2628 2527 2565 2477 2514 2473 2510 2440 2473 2352 2438 2362 239S 2362 2400 23^7 2407 2403 2436 2284 2336 2331 2319 2324 2235 2275 2272 2316 2314 234S 2324 2386 2504 2497 Bracketed number shows that the station is excluded in the equations of condition. MAGXETIC SURVEY OF JAPAX FOR THE EPOCH 1895.0. 109 _X1A/^I. {Continued.) X, Y, Z, au < + S] 1 + ' + Azimuth N-W-S-E-N Altitude! No. Obsorzed Cak-iilatod Obs.-Cal. Obs.-Cul. Olis.-Cal. >< -34945 -34912' + 102 - 50 — 33 T 114 T iiS 334 - 16 ' 253 -34456 -34418 + 11 + 13 - 38 17 42 50 - 66 254 -34562 -34558 + 16 4- 20 - 4 26 26 51 - 9 -55 -34950 -35022 + 35 33 + 72 48 87 317 + 56 256 -35357 -35231 + 112 + I - 126 112 169 I - 48 257 — 35357 -35315 + 214 - 45 - 42 219 223 348 - II 258 -35376 -35399 + no - 30 + 23 114 116 345 + II 259 -35S64 -35608 - 332 - 98 - 256 346 431 196 - 37 [260] -35765 -35421 -t- 58 - 50 - 344 77 352 319 — 77 261 -35384 — 35257 - 84 + 77 - 127 114 171 137 - 48 262 -36130 -35586 + 209 + 32 - 5-14 211 584 9 - 69 263 -36164 -35902 — 200 - 83 — 262 217 340 203 - 50 [264] -35S61 -35932 - 172 - 83 + 71 191 204 206 + 20 265 -35739 -35499 + 39 — 5 - 240 39 243 353 - 81 266 -35436 -35209 + 366, - 30 - 227 367 432 355 — 32 [267] -34S06 -34727 -35007 + 56 + 6 - 79 56 97 6 - 55 268 [269] -35058 -35021 + 114 + 1 - 37 114 120 I — iS 270 -34002 — 33933 + 91 + 3 - 69 91 114 2 - 37 271 -34084 -34057 + 84 2 - 27 84 88 359 - 18 272 -33537 -33467 + 6S + 16 - 70 70 99 13 — 45 273 + from the horisou toward the zenith. from the horisou toward the nadir. 112 A. TANAKADATE. T^ELE Observed and Calculated Values of Maouetic Elements ^-(.. 274 275 276 277 2S0 [281] 282 2S3 2S4 28 5 287 288 2S9 290 291 292 293 294 St;ition. Nawari Kôti (Itnti Snsaki Nakaraiira Uwazinia ^\':lkalniya Yiihatahama ... Saganoseki Saiki Oita ^Matiiyaina Kuzu, Tyo Kuma „ „ Imabaru Kawanoe iMarngaine Takamatu Tonosyô Zaikôzi Miyazaki racketed number Height in km. Year. Lati- tude. Longi- tude. North Coiii]jt. X Ob- Caleu- served '■ lated 0.00 0.00 0-35 0.00 0.00 0.00 o.oi 0.00 o.co 0.00 0.00 0.00 0.33 0.53 0.00 0,00 0.00 0.00 0.00 0.00 0.00 IS96.G5 33 26.0 1896.65 33 32.8 1896.66 33 41.0 1896.67 33 34-0 1896.67 32 57-7 1896.69 33 13-2 IS96.69 33 32.0 1896.70 33 27.4 1896.70 33 14-5 1896.71 32 56-9 1896.72 33 I5-0 IS96.72 33 52.0 IS96.73 33 33-8 IS96.73 33 39-4 1896.74 34 04.0 1896.75 34 02.0 1896.75 34 16.9 1896.75 34 21.0 1S96.76 34 29.0 IS96.52 32 24.2 1896.52 31 55-2 134 03.0 ^33 33-3 ^33 53-0 133 I7-S 132 55-0 132 34-5 132 34-5 132 25.7 131 53-3 131 52-5 131 36.0 132 45.0 132 5S.5 132 53-5 133 01.5 133 49-0 134 02.8 134 10.5 131 36.8 131 25.3 30931 30S83 3097S I 30894 30879 : 30815 30974 3o<,69 31202 31155 31119 31105 31053 31000 ... 310;! 31298 31 1 73 I 31215 j 31272 30992 ' 31203 30901 I 30S6S 30977 30947 30915 30924 30827 \ 30771 30804 30725 30766 30615 30683 ; 305 ;o 30542 30510 3150S . 31481 31660 '■ 3'659 West C'ompt. Y Ob- I Calcu- seived 1 lated 2340 j 2336 2380 I 2365 I 2384 ! 2376 2354 ' 2349 2289 2290 231S 2355 2380 2369 2339 2209 2319 2413 2372 2403 2451 2482 2214 2205 2296 2343 2427 2379 2393 2451 2427 2430 2430 2463 2466 24S1 I 2480 2212 2135 shows that tlie station i.s exehided in the equations of condition. MAGNETIC SURVEY OF JAPAN FOR THE EPOCH 1895.0. llo ]XLA^I. (Continued.) X, Y. Z, and Intensity and Direction of DistniLing Forces. Upward Z Compt. North Compt. AX West Compt. AY Upward Compt. AZ + 1 <] + iÎ ''X 1 Azimuth X-W-S-K-X Ahitude. No. Observed Calculated Obs.-Cal. Obs. Cal. Obs.-Cal. -334^3 — 33393 + 48 + 4' T - 50 48 69 0 5 - 46° 274 -33657 ; -33656 + 84 + «5 — I 85 85 10 - I 275 -33S46 -33712 + 64 + 8 - 134 65 149 7 — 64 276 -33647 -33567 + 5 + 5 - So 7 80 45 -' 85 277 -33293 : -33195 + 47 — I - 98 47 109 359 - 64 278 -33512 -33576 + 14 - 15 - 36 21 41 313 — 60 279 -33927 -33927 + 53 - 25 0 59 59 335 0 2S0 -34054 -338S4 — 170 - ... [281] -33853 -33810 + 125 - 18 - 40 126 132 352 — 18 282 -33527 -334S4 - 57 - 27 - 43 63 76 205 - 34 ^^3 -33740 -33909 — 211 - 24 + 169 212 271 186 + 39 284 -34233 -34241 + 33 - 14 + 8 36 37 337 + 13 285 -33934 — 33838 + 30 7 - 96 31 lOI 347 - 72 2S6 -33958 -33967 - 9 + 10 + 9 13 16 132 + 35 287 -34432 -34380 + 56 0 - 52 56 76 0 — 43 2S8 -34226 -34178 + 79 3 _ 48 79 92 358 - 31 289 -34480 -343S1 + 151 — 33 - 99 •55 184 348 - 33 290 -34482 -343''8 + 113 + 16 - 94 114 14S 8 — 40 291 -34514 -34496 + 3^ + I - 18 32 37 2 - 29 292 -32980 -32953 + 27 + 2 - 27 27 38 4 - 45 293 -32483 -32466 + I + 70 1 - '7 70 72 89 1 — 14 294 * + from the horison .toward the zenitli. — from the liorison toward the nadir. 114 A. TANAKADATE. TABLE Ol)served and Calculated Values of Maonetic Elements ÎSO. Station. Height ^- [ lear. in km. Lati- tude. Longi- tude. North Compt. X Ob- Caleii- sorved lated West Compt. Y Ob- I Calcu- sei'ved , lated 295 Miyakonczyô.. igö Nakamati 297 Küvama 298 Kagosima [299] Itiki, Satuma. 300 Makurazaki .. [301] Kaseda [302] Yokogawa 303 Hitoyosi .. 304 305 306 Yunomae.. Yatusiro .. Minamata 307 Simabara. [308] Nagasaki 309 Sasebo .... 310 3" 312 Matiyamaguti , Kumamoto Miyadi [313], Mamibara 314 315 Yanngawa . Hukuoka.. 0.14 1896.53 31 42.S 131 03.0 o.oD 1896.53 31 26.2 131 1 1.3 o.io 1896.54 31 20.5 130 55.5 0.00 1896.54 31 35-4 130 32-S coo 1S96.55 31 41.6 130 16.0 0.00 1896.55 31 17.0 130 16.5 o.oj 1S96.56 31 25.0 130 19.1 0.18 IS96.56 31 54.2 130 41.5 0.12 IS96.57 32 I2.I 130 46.5 0.66 1896.57 32 15.8 130 59-0 0.00 1896.58 32 29.7 130 36.0 0.00 1896.5S 32 12.4 130 23.5 0.00 1S96.59 32 46.1 130 22.5 0.03 j 1896.59 I 32 45.0 129 52.5 0.00 i 1896.60 2^ 10.5 129 44.3 0.00 1896.61 32 27.5 130 10. s 0.02 1896.61 32 48.0 130 44.0 0.51 1896.62 32 55.8 131 07-4 0.54 1896.62 32 39.2 131 09.5 0.00 ' 1896.63 33 09.6 130 24.8 0.00 1896.63 33 35.2 130 23.8 T I T 31759 ; 31769 31846 j 31841 31969 j 31901 31784 j 31869 32242 I 31870 31893 I 31999 51649 31951 31751 1618 31644 31611 31635 31986 31304 31769 31600 31571 31690 31509 31578 1376 31456 31625 31282 31634 31455 31418 31365 j 31399 3145^ 31341 I 31375 31114 ! 31235 ^043 2041 2072 2098 2054 2036 2008 2071 2231 2089 :i96 Î18 2083 2015 2038 2125 2174 21S7 2219 2169 2255 2260 2452 I 2247 2295 I 2312 2170 ; 2207 2277 I 2269 2122 2292 2063 i 2250 2298 2321 2390 : 2388 Bracketed number shows that the station is exchided in the equations of condition. MAGNETIC SURVEY OF JAPAN FOR THE EPOCH 1895.0. 115 XVI. X, Y, Z, and Intensity and Directinu of DisturLino- Forces. Upward Z Coinpt. North Compt. AX West Corapt. AY Upward Coiupt. AZ § = - t 'y. -1 Azhnuth N-W-SE N Alti tilde. No. Oliservod Calcuhitoa Olis. -Cal. 01>s.-Cal. Obs.-Cal. -1 -32267 -32344' - T 10 - 55 ^ T 4- 77 56' 95' 260° 4- 0 54 295 -32021 -31995 + 5 - 13 ! - 26 14 30 291 - 62 296 -31909 -31962 + 68 , + 36 4- 53 77 93 28 4- 35 297 — 32374 — 32357 - 85 - 63 17 106 107 217 - 9 298 -324S6 -32560 4- 370 + 148 4- 74 399 405 22 4- II [2.,9] -3219S -32090 - 106 + 74 1 - icS 129 168 145 - 40 300 -32274 ! -32228 '" _ 46 ... - [31] -31S93 -32666 - 102 4- 71 4- 773 124 783 145 + 81 [3 '2] — j2öj/ -32980 - 26 4- 124 4- 143 127 191 102 4- 48 303 -32S32 -329S7 4- II 4- 31 4- 155 33 158 70 + 78 304 - 33442 -33370 4- 64 4- 2 — 72 64 96 2 - 48 305 -3331^"; - 33 1 oS 4- 296 4- 52 — 210 301 367 10 - 35 306 -33564 — 33757 — 205 5 4- 193 205 282 i8i + 43 307 -34521 -33905 4- 191 4- 205 - 616 280 677 47 - 66 [308] -34351 -34449 - 80 - 17 + 98 82 128 192 4- 50 3 9 -33360 -33463 — 9 — 37 4- 103 38 no 256 4- 70 310 -33467 -33676 - 173 + 8 4- 209 173 271 177 4- 50 311 — 33837 -33698 + 53 - 170 - 139 178 226 287 — 38 312 -341S1 -33386 - 53 - 187 - 795 194 SI8 254 - 76 Vi^i^ -34145 -34196 - 34 — 23 + 51 41 65 214 4- 51 314 - 34678 -34698 - 121 4- 2 + 20 121 123 179 + 9 315 * + from the horison toward the zeuitli. from tlif horison toward the nadif. 116 A. TANAKADATE. Ti?LBLE Observed and Calculated Vaines of Mairnetic Elements No. Station. Height in km. Year. Lati- tude. Longi- tude. North Coiiipt. X AVest ('ompt. Y Ob- Calcu- served lated Ob- .served Calcu- lated 316 Kokura 0 / 0.00 i i8q6.6j. ;; ;;.; i3o°53.'5 131 11.3 131 30.0 130 57.0 129 59-5 Tl T 31075 ^1072 2574 2416 2413 2502 2353 T 2438 2397 2397 2350 2359 317 318 319 320 Nakatu Nakamatama... Kuma, Bungo... Karatu 0.00 0.00 0.08 0.00 1896.64 1896.65 1896.65 1896.66 33 36.5 33 36-0 33 18.5 33 26.5 31047 31091 31181 3 1 201 31131 31098 31260 31334 Bracketed number shows that the station is exckided in the eipiations of comlition. MAGNETIC SURVEY OF JAPAN FOR THE EPOCH 1895.0. 117 SLA^I. {Continued.) X, Y, Z, and Intensity and Direction of Disturbing Forces. Upward Compt. Z Xnrth Compt. AX ^\■est Coiiipt. AY Upward Compt. AZ > + + Azimuth X-W-S-E-X AltitudeT No. Observed Calculated Ote.-Cal. Obs.-Cal. Obs -Cal. T -34958 T -34874 V + 3 + 136 - 84' Y 136 160' 89° - 0 32 316 -34555 -34451 - 84 + 19 — 104 86 135 167 - 50 317 -3+456 — 34338 7 + 16 - 118 17 119 "4 - 82 318 -33531 -34186 - 79 + 152 + 655 171 677 "7 + 75 319 -34633 -34673 - 133 - 6 + 40 133 139 183 + 17 3^0 * + from the horisou toward the zenith. — from the horisoii toward the nadir. 118 A. TANAKADATE. Alphabetical List of Stations. Stations. :so. Stations. 2s'o. Stations. Ko. I G Hukusinia, Iwasiro 209 A Hukuyama, Osima 141 Alia^iri [132] Gamon 164 Hukuyama, Bingo 268 A 1)11 ta 99 (tCI-O «5 Plunama [104] . Adigasawa 192 Gihu 7S Hûren 116 ! Ai 263 H Huzi [48]. ..[51]. Aikawa 30 Hagi 25s Ainonai 131 Hakodate 136 I I Akasi 239 Haniada [260] lida So Aklta 1S7 Hamaliata [269] liyania 20 Akka [173] Ilanamaki 166 Ikuno 232 AkG 23S Hasizu 235 Ikusazawa [1S2] Anazawa 174 Hatiman, Mino 86 Imabaru 2S8 Aomori 197 Hatiman, Onii 226 Iinaiti [264] Arinia 249 Hatiuohe [169] Ippongi 193 Asahikawa III Hatiüzl 2 Isinomaki 181 Asama [34] Hiromibara [53]. ..[55] Itiki, Iwami 261 Asyoro 155 Hirosaki 191 Itiki, Satnma [299] At a mi [40] Hirosima 253 Itinomiya 202 Atumi [214] Hitoana [59]...[6i] Itoigawa 16 Atusanupuri [159] H i toy OS i 303 Iwaizumi [175] Awano 259 Hongu 247 Iwaniizawa [108] Honzyô 1 88 Iwanai 102 E Hudisawa 43 EbihU 28 Hukaya 198 K Esasi, Kitami [126] Hukuoka 315 Kagosima 29S Esasi, Osima 140 Hukasima, Sinano [82] Kakiidate [1S5] MAGNETIC SURVEY OF JAPAN FOR THE EPOCH 1895.0. 119 TA-]BIj"E XVII. {Continued) Ali»lial)etical List of Stations Stations. No. Stations. No. Stations. No. Kamaisi 179 Knma, Bungo 319 Memnro 152 Kameyama 72 Kuin ig.ii 38 ^I id one [45] Kamiiti 241 Kumamoto 3" Midzusawa 165 Kami^uwa 12 Kiirosaka 266 Miliara 25^ Kamo [26] Kuriima [15] Mikkaiti 98 Kamiyasiro 74 Kusimoto 248 Minabe 245 Kanazawa 93 Kntf) 139 Minamata 306 Kara tu 320 Kntnkake [10] Mito 205 Kariwano [1S6] Kiizi, Kikntyü 172 Mit u ike [56] ..[58] Karnizawa 9 Knzn, lyo 286 ]\Iiyadi 312 Ka?eda [301] Kyoto 227 Miyako [176] Kasiwazaki [^3] M ^liyakonozyo 295 Katikawa 76 Maebara 203 Miyatii 229 Kawanoe 2S9 Maegasu 70 Miyazaki 294 Kesennuma 180 Makado 196 Miyosi 262 Kisaratu 204 Makurazaki 300 Miyota 8 Kiyosu 77 Mainibara [313] ^Lmbetu 128 Koga --5 Mariigaiiie 290 Mori 137 Kocfota 163 Maslke 114 Mcirioka 167 KôJui L4] Matiyamagnti 310 Moyoro 150 Kokura 316 Matne 265 Mi)znmi 97 K'lminatotaira (Saiueura) Koiiioro 170 [7] Matnida >ratiimoto 35 13 ]\Iiirakanii Mu raya ma 215 [52] Köti 275 Matnô 81 Miirodzumi 255 Kdwa 67 Matus-.ika 251 Mynzi 242 Köyama 297 Matuyama 285 N Klima, lyo 287 Matnziki 42 Xag.iliaina 88 120 A. TANAKADATE. TABI.E XVII. {Continued: Alphabetical List of Station?. Stations. No. Stations. No. Stations. No. Nagamine S7 X'liniata 37 Utoti 276 Nagano 19 X^iiniazii 63 Util, Saganii 44 Nagaoka 22 X'u[ipainamoi [121] (Itu, Tokati [Î56] Nagasaki [308] Ozasa [32] Nagasima 250 0 Nagoya 69 Obama 230 P Nakaniatama 3'8 Odate 190 Porokanniikotan ["3] Nakamati 296 Odawara 39 Poronai 127 Na kail iura 278 Ogi 31 Pösinaipitari [iiS] X.ikatii Nakatngawa 317 79 Ognni, Eikiityu Oguni, Uzen ['77] 2IÔ R Puuisii 134 Nakayama [168] Oliotnkawa [112] Nainie 207 Oita 2S4 s Nanau 94 Okayama 237 Saganoseki 282 Nara 240 Okazaki 66 Saiki 2S3 Nanimi 68 Okiiruniatomanai ["9] Sakai 231 Nawari 274 U]ii:i [194] Sakata 2'3 Nayoropt [120] Oinati 14 Sa k lira 199 Xemuro [161] ( 'niiya [62] Sapporo 107 Niigata 25 ()no, Etizen 91 Sarubutu [125] Xikkr. 221 Ono, Kikutyü [171] Sariihasi [3] Nisina^iuno 223 dsato 273 Sarupt. 145 Nisinoto 65 Osyanianlje 100 Sasayama 228 X'( garni 130 Osvatinai 146 Sasebo 309 X'dlmka [147] Otasdi 153 Sawara 200 Xdmngi 83 Otaiii 105 Sekiyaina iS XTisiiT) 189 Otarii-Mydkenzan 106 Send ai 162 MAGNETIC SURVEY OF JAPAN FOR THE EPOCH 1895.0. 121 T^BLE XVII. (Continued.) Alphabetical F^ist of Stations. Stations. No. vStatioiis. No. Station. No. Setana 138 Takahasi 270 Umagaesi [47] Sibata 27 Takaiiiatu 291 I'minokuti 5 Sibetii 135 Takasaki Takata 36 17 I'rakawa Usuta [148] 6 Sibetya [158] Takayaniu 84 Utunoniiya 224 Sima})ara 307 Ta kell 11 Tanabii 90 [195I Uwazima 279 Simizu 64 Tazima 219 w Simoda [41] Teradomari [24] Wakamatu 21S Simoinnai 183 Tesio 117 Wakaniiya 2feo Tikatnyii [246] AVakasakanai [122] Sinryü [160] Tip-Yabusi no Wakasare i3Z] Sinzyö 212 Tiribetu 14? ^V'akayama 243 Sioya 92 TJ.a 75 Wakkanai 123 Tökamati 21 Wakiniati 272 Siramika 157 Tokusinia 271 \V:isizaki 29 Sirasitouiari "5 Tokyo \ii ^Vatari [20S] Sirimi 142 J) Tomakoiiiai lb [M4] Waziina 95 Sitata 254 Tuno 17S Y Soratipt 109 Tonosyc) 292 Yahataliama [2S1] 8üya 124 Tottori 234 Y'amagata 211 Toyaraa 96 Yamaguti 256 Sukagawa 222 Toyooka 233 Yanagawa 3'4 Sumoto 244 Tnzyö [267] Yatusiro 305 Tu Tugawa Yobetu [«03] Susaki 277 73 217 Yokkaiti 71 Siittu lOI Tu ruga 89 Y'okogawa [302] Syari 133 Tuwano 257 Y'okote 1S4 Syorusam 154 Tuyama Tyosi 236 201 Yonezawa Y'osida 210 [46] Syoya 149 Tyürui u 151 Y übet u Yuiioniae [129] 304 T I'eda, Sinano II z Tad ami 220 Ueda, Iwaki 206 Zaiknzl 293 122 A. TAXAKADATE. § 11. Vertical Current. It is usual in magnetic surveys to calculate the amount of the vertical current of electricity by taking the line integral of the magnetic force round the periphery of the country. The same was tried here in the circuit indicated in Fig. 4 by taking the integral along the co-oi'dinate lines thus : — IÜ which may be put for numerical calculation «y = ^^^(Y„ cos w,-Y, cos ^,)j;.-^(X„-X,)J^ where the suffixes n, 5, u\ e, denote the values of those quanti- ties on the north, south, west and east side of the circuit, and R the mean radius of the earth ; the positive sense of the co- ordinates X, y, z are north, west and up respectively.* Per- forming the operations above indicated we have R 4 ^^(Y,, cos (p,-Y, cos f ,)J/= 0.03973 x length of 1° 4^J(X.-X,)J^ = 0.04146 X whence w= -0.00173 x -^-"''' ^ ^^' x .0174.") 4;r = — l.i31 c.g.s. el. mag. units. The area of the circuit is '3.701x10' sq. kilom. hence the mean current density is -1.331x10 ~~, .-7^ =-0.027 Ampere per s< f 129° 130° 131° 1 132° 133° 134° 135° 1 136° 1 137° lf>° % 45° W° 43° 42° 41° 40° 39° 38° > 1 — 0.171 37° - -0.154 — 0.091 36° — 0.299 —0.246 — 0.191 - 0. 1 34 -0.075 —0.014 35° — 0.262 -0.213 -0.163 — 0.081 — 0.1 r I -0.054 0.003 ' 0.079 0.062 34° — 0.221 -0.177 - 0. 1 3 1 — 0.029 0.024 0.136 33° — 0.176 -0.135 -0.093 1 — 0048 —0.000 0.049 O.IOI 0.154 32° -0.053 — 0.012 0.032 0078 31° 0.028 0.067 0.109 :^/- 129^ 131)° 131° 132° 133° 1 1 134° 135° 136° 137° MAGNETIC SUnVEY OF JAPAN FOll THE EPOCH 1895.0. 12Ô Longitude and Latitude, Calculated froui the Formulas for Horizontal Force and Declination. I.'IS« VV.)' U(P Ul UJ^ U:i° 144° 145 14(>= / c — 0.426 1 1 4<> 45° 1 -0.435 -0.346 — 0.266 -0.254 -0.353 — 0.178 — 0.089 — 0.017 0.00 1 0071 0.092 44° -0.356 -0.274 -0.194 — 0. 1 89 —0.103 0.159 48° -0.274 -0.II3 -0.030 4'*° 41° -0.195 — 0. 1 17 — 0.041 -0.039 —0.192 — 0. 1 1 7 0.035 ! 40° — 0. 1 1 3 — 0.041 0.033 0.106 0.177 :{<)° 38° 8ΰ ••{5° —0.104 -0.036 0.033 0.105 — 0.027 0.048 0.039 0.107 0.176 0.113 0.178 0.246 0.245 0.122 0.185 0.313 0.19s 0.255 0.313 i :i:i . 1 lil' 1 ■ i :n° ias= i.iip UO^ Ul° wr u;r 144^ 145 14<) c 120 A. TAXAKADATE. . dY flX ax oi/ which in polar co-ordinates becomes 1 / OY ,., 1 OX \ or replacing X, Y by Hcosrî and Hsino, we have i ( OH . . , „ , nd TT • > , v: = -p < -^ -sHio + Hcoso— H sino to- ç 4- K ( i).2 -45268.0 -44030.0 -45279.5 -44020.9 + 11.5 - 9-1 VI n 15956.0 15956.3 — 0-3 6414.0 6413-9 4- 0.1 -45267.0 — 45268.0 4- i.o IX 16829.0 16833.0 - 4.0 5990.0 59S4-3 + 5-7 -44403.0 -^4407-3 4- 4.3 128 A. TANAKADATE. All these three surveys give the line of no current through the middle of the country ; in Japan the current is upward on the Pacific side and downward on the Siberian side ; in Austria it is upward on the north and downward on the south ; in Great Britain, upward on the east and downward on the west. Whether these distributions of current density show the real average state of things during the surveys of the respective coun- tries or not is very doubtful. The fact that the line of no current runs thi'ough the middle in each of those countries inspite of different aspects of their distributions, seem to indicate that they are the result of uncompensated local disturbances and inadequacy of the empirical formuhe to a large extent, if not wholly. Considering that these currents depend upon the dif- ferences of differential coefficients of the ol)served elements, ob- servations of greater refinements than the present, both in con- struction of instruments and distribution of stations, will be necessary in order to settle the question more definitely ; certainlv these currents can be accounted for by the probable errors in the constants of the empirical formulse, at least in the case of Japan. Even in Great Britain, where the survey was very care- fully carried out by excellent hands, the two sets of lines of equal currents present very different appearances according as they are derived from the district equations or general equations for the whole country (See Map 9a). Under such circumstances the most fascinating subject of the motion of electricity from or towards the earth's surface must be left untouched, be it due to the diurnal motion of the earth or transference of ions with water vapour and the like. These will probably be better elucidated by pursuing other methods of investigation. It may l)e a good plan to improve MAGNETIC SUKVEY OF JAPAN FOU THE EPOCH 1S9Ô.0. 129 those empirical coefficients by imposing the condition of irrotation- ality among them, as was suggested by the writer on previous occasion. This being premissed, the vahies along the line of no current will be represented nearer to the truth than the rest and should be taken in preference to values at other places in deducing the magnetic constants of tlie wliole globe. § 12. Vertical Variations of Magnetic Elements. The variations of magnetic elements due to difterence of level has recently l)een computed l\v Prof. I> arising from the heterogeneity of the atmospheric air is utterly insignificant being only 6.4 x lO^V per kilometer in middle part of Japan, taking the susceptibility of the air to be 3.2x10-' g-z/is.4 kno,,,.^ Hence putting u=v = o and ,0=0 we have MAGNETIC SUKVEY OF JAPAN FOR THE EPOCH 1895.0. 131 öX r)Z dz ~ ÜX fiY dZ dz ~ ÖV/ öZ ox dz dx OY expre;:;sing vertical v;iriutioDS of rectangular cuuipoiients in terms of their liorizontal variations.* It appears at first sight that the curvature of the earth surface may he neglected for the extent of the country covering only a few degrees of longitude and latitude ; calculation shows, however, that it plays an important part ; transforming, therefore these equations into polar co- ordinates, we have OX J r d'A ^ OS K V dip J Y _ 1 / 1 '''>^ _y dz ~ K V cos (f d'A dZ 1 / OX 1 OY ^. , ,„\ dz Vi\ df ^ coi^(p dk » ^ J V\. being the mean radius of the earth, I

ter of V. Neuinanu's " Theoi'ie des Potentials" where the saiijc problem is dibcusrinl, though apiiruaelied iu diilereut way. 132 ' A. ÏAKAKA.DATE. OX OH . -u • ^ do dç> dip d

, , ,T .. /, 0^ -ör=-or^s^+"'^^"^^r J^= JH ^ j^ ^^^ ,0^ 0^ 0^ Oç? After computing the vertical variations of the rectangular com- ponents in this way, those of the observed elements '\ ^, H, can couvenientlv be found as follows : — OH dz dz . OX , . , OY = cos () - 4- sin u dz i)z Or) 0 , _, Y" = -."t'' os ~ âr ° X cos o / OY , . OX \ =^H-\-o^-^°'^-o.rJ 00 ^t<'-^ '^^ ^dz~~l)z^ ° H cos 0 ( O'A , ,. Oil \ -^l-oir-^^^-oT-j cUid —4 — = -^ — Hsec^? Oz Oz The reduction to the sea level of § 8 ^Yere calculated by these ibrnudai using the hrst approximate values used for deducing the annual variations. .Tables XX to XX Y give data and values of these varia- tions for Ja})an, Austria and Hungary, and Great Britain, at MAGNETIC SURVEY OF JAPAN FOR THE EPOCH 1895.0. 133 five points in each, distribnted so as to cover different quarters of the countries. In Great Britain the Central Stations of the Districts I, III, V, VIL and IX are taken as representatives. The last figures of numbers exceeding 20. 0 in those tables will be slightly affected by taking into account the difference of principal curvatures of the earth surface in various latitudes, but since their proljable errors come to the same order of magnitude in such cases, the mean radius is used for simplicity. 134 A. TAN AK A DATE. a^AlJLE XX. Duta I'ur the CalciiUiLion uf Vcitical Wiriatu)!)« of Magnetic EleuiciilfS m Japan . I. II. II r. lY. Y. / EufGr. 142° 30' 140^30' 1 38° 00' 1 34° 00' 131° 00' Ç N 43° 30' 3«° 30' 36° 00' 34° 30' 32° 30' H ^265 5 8' 28677' 29760' 30622' 3159«' o \y. 5°55'4 5^03:2 4°45'7 4° 39-6 4^02:2 0 -5;°i3'i -5^° 13^1 -49° 41-9 -4«° 27:5 -46° 27:3 X 26415' 28566' 29657' 30521' 31520T Y 2740 2526 2471 2488 2224 z -41237 -37000 -35089 -34566 -33251 X 49050 46814 46009 46182 45873 OH Ö^P^i'JL -4247 -37^-7 -353-8 -335.5 -3144 an. i' T y v ^^ -9;- „ 52.1 59.8 73.7 99-7 117-8 -^-perl° 15:3 i6.'6 17:5 18:7 19:7 -|f- ;, 15-7 ii-9 8.0 2:5 -1:9 -~ — per 1° -60:0 -65:7 -69:2 -72'4 -75'7 -^- „ - 7-8 - 6:s - 7:1 - 8:8 - 9-7 MAGNETIC SUTJVEY OF JAPAN FOP. TTTE EPOCTI 1890.0. 13') TABLE XXI. Vertical Variations of Magnetic Elements in Ja p a n . I. II. III. IV. V. —^ — per kilDni. Uz ^ — 12.2 -13'- -i3'.8 - 146 Y -is' 2 (3h/R)X -12.5 -13-4 + .2 — 14.0 + .2 -14.4 -14.9 DifF. + •3 9Y ,.. — 7c — per kilom. Y - 4.0 - 3-0 T - 30 - 3.6 - 37 (.31i/R)Y - 1-3 — 1.2 — 1.2 — 1.2 — I.I Diff. — 2.7 - 1.8 — [.8 - 2-4 - 2.6 f)Z , ., — ^ — ])cr kilom. '■■■ 19.2 17-5 t6!8 16.9 Y 164 (3h/R)Z 194 0 17.4 16.5 16.3 157 üift". + .1 + ■3 + .6 + 7 9H , ., — 7-~ per kilom. Oz *■ -12.5 -13'.^ V — 14.0 - 14.8 -15.4 •(3h/R)H -12.5 -13-5 — 14.0 -14.4 -•4 -14.9 Diff. C) 0 0 -•5 91 ... — r— per kilom. — 22 9 Y — 22.0 T -21.7 T -22.4 -22.4 -(3h/R)I -23.1 — 22.0 -21.7 -21.8 -21.6 Diff. + .2 0 0 -.6 -.8 —-per kilom. -o.'35 -o.'22 -o'2i -0:27 -o.'29 dz -^per kilom. -o.'oi +o.'oi +0.02 +0.01 +o'oi dz ^ * Since Z is negative upward, + correction means upward diminution in the intensity of Z. 136 A. TANAKADATE. TABX^E XXII. Data for the Calculation of Vertical Variations of Magnetic Elements in A list r i a a n d Hu n g a r y. IV. Y. ;. E of Gr. 15° 15° 20° 25° 25° l)d dX }> dd fiif }} m 9^ — o.'4 — o.' I — 5 .'8 — 1 1 -5 — 1 1 .'2 3o!7 25^2 27. '2 3o'3 24.'8 -45-5 -52-'5 -50-7 -47-6 -54-6 — 6'o ~- y'.o — 5-8 — 4'2 — 5-2 MAGNETIC SURVEY OF JAPAN FOR THE EPOCH 1895.0. 137 TABLE XXIII. Vertical Variations of Magnetic Elements in A list r i a a n d Hu ng ary . I. II. III. IV. V. OX , .. —, per kilom. - 7-8 - 8.8 - 8.8 - 8.6 - 94 -(31i/Pv)X - 9.2 — 10.2 — 1 0.0 - 9-7 -10.7 Diff. + 1.4 + 1.4 + 1.2 + I.I + 1.3 OY , „ -, -per kiloni. - 0^9 V — 1-3 V - 0.6 + 0^4 — 0.2 -(:]li/R)V - 1.6 - 1.8 — 1-3 — .8 — I.I Dift". + •/ + .5 + .7 + 1.2 + -9 h'A . .. per kilom. Oz ^ i8.'5 I/-/ iS'.i 18.5 17.8 -(31./K)Z 19.8 - 1-3 18.2 19.0 19.8 - 1-3 18.4 Diff. ~" -5 - .9 - .6 OH , ., — ïj--per kilom. T - 8.9 - 8^8 - So - 94 -(3h/R)H - 9-3 -10.4 + 1-5 - 10.3 - 9-7 4- 1.2 - 10.7 Difï: + 1.5 + 1-5 + 1-3 01 , ., per knom. Oz '■ — 20.0 — 19.8 — 20.2 V -207 — 21.0 -(3h/R)I -21.9 + 1.9 — 21.2 -21.5 + 1.3 — 22 I -21.3 Diff. + 1.4 4- 1.4 + -3 (In , .1 per kilom. ()Z ^ + o'o7 + o.'o4 + 0.09 + o.'i7 4-o'i I per kilom. + o.'o6 + o.'o; + o.'o6 + 0^03 + o'io Z is negative upward,+correction means upward diminution in the intensity of Z. 138 A. TANAKADATE. TABLE XXIV. Data for the Calculation of Vertical Variation of Magnetic Elements in Great Br it a i n . T. in. V. yil. IX. yîWofGr. 4° ^1-5 2° 05 .'9 7° 37-9 3° 08.0 4° 32:6 f 56°3S.'2 53° 24:2 54° 02:7 51° 05:3 51° 41-9 TT T " T "' y a 16011 17313 16761 18206 17863 0 20"^ 58.4 i8°5i.'8 22° 03:9 18° 38:4 I9°35.'5 ^ -70° 57-3 -68° 53:6 -69° 52:6 -67° 32:1 -68° 05:2 X 14950' 163S4' 15534^ 17-52' 16829"^ Y 5731 5598 6296 5819 5990 z -46381 -44853 -45744 -44030 -44403 1 49069 48078 48717 47645 47863 dip 1'"' " — o^^v •4'-'-+ - ^^^ y ^.^KJ.KJ 4^.5-/ OH T - ^7-7 - 59-3 Ï - 80.2 T - 75-7 T - 62.8 ^0 TO i3'i 14.6 22:6 12-5 19:4 32-5 30:3 32:8 30:5 30:8 ^1-1° -34-5 -37'2 -35^4 -41-4 -3S-'7 dX " - ^'7 - 6:3 - 8:2 - 8.'i - Co MAGNETIC SURVEY OF JAPAX FOE THE EPOCH 1895.0. 139 Veiiicul Variation of Magnetic Elements in Great B r i t a i n . I. iir. Y. VII. IX. — .^^-per kilom. - 6 o - 62 :>■/ - 6:9 - 64 -(3h/Pt)X - 7.0 ~ 7 7 ~ 7-3 - 8.1 - 7-9 Difï". + 1.0 + 1-5 + 1.6 + [.2 + '-5 ^^' ^ -I — ;,. -per kilom. - 2.5 - 2.3 — 2.8 - 2.'5 - 2'.3 -(31i/R.)Y - 2-7 - 2.6 - 30 - 2.7 + .2 - 2.8 DifF. + .2 + .3 + .2 + -5 — ;^ per kilom. 19.6 19-3 1' 19.7 T 19.2 I9'2 -(3b/R)Z 21.9 21. [ 21.5 20.7 - 1-5 20.9 Diff. — I. S — 1.8 - 1-7 ^^y per kilom. - 6^5 - 6.6 - 6.3 r - 7'4 - 6.S -(3h/R)H ~ 7-5 - 8.1 - 7-9 + 1.6 - K6 + 8.4 Dift: + I.O + I 5 + 1.2 + 1.6 91 ... — ,7 —per kilom. fin; ^ - 20!/ r — 20.4 — 20.6 — 20.5 -20'. 3 -(3h/R)I -23.1 — 22.6 — 22.9 + 2.3 -22.4 + 1.9 — 22.6 Diff. + 24 + 2.2 + 2.3 .— /^^per kilom. or: ^ — 0.04 -0.03 — o.'io -0:03 — o.'oo per kilom. fis + 0.'02 + o.'o6 + o.'o6 + o'o4 + o.'o6 * Since Z is negative iipw:iril, + correction means ujiward diuiinutitm in tiie intensity of Z. 140 A. TAXAKADATE. Comparing those variations with the coefficients of the lirst term of harmonic expansion we observe that the agreement is fairly close. It is interesting to remark that even from surveys made over so small portions of the earth surface, we can see where the principal origin of the terrestrial magnetism lies, that is in Gauss's sense. Gausses Circuit. Gauss in his classical example of the Göttingen-Milan-Paris circuit, might have gone a step further and found those varia- tions approximately. Taking his data and reducing to c. g. s. units we have ^ Arhitrary À ç> o a H unit>. Göttingen 9° 58' 51° 3-2' 18° 38' -67° d6' 17813' =0.50983 3Iilan 9° 09' 45° 28' 18° 33' -G3° 49' 19949 '=0.57094 Paris 2° 21' 48° 52' 22° 04' -G7° 24' ISlOP =0.51804 Whence the rectangular components are X 16880' Göttingen Milan 18913 Paris 16775' which give uniquely .5692' 6347' 6800 -43942' -40572' -43485' X = 17522.8 + 137.7 J/ - 353:7 J^ Y= G279J- 112.9 J;.- 92'.7J^ Z = -426G6!3 + 141.3 J/- 574!.5J^ where J;>=(;.-7°.16)°E., Jçc=(^-48°.62)° expressed in degrees. M AGNETIC SURVEY OF JAPAN FOR THE EPOCH 1895.0. 141 With these vahies the vertical variations at the mean point, i=7°.lG and ç = 48°.G2, come out: — ^i^ = - 7;!) -^ = - à -^ = + i'^>^ -(3h/R)X =- S.2 -(3b/R)Y =- 3.0 -(31./R)Z ^+20.1 Diff. =~rä3 Diff. =+ O.l Diff'. =- -2.1 He mio-ht have thns inferred the seat of the terrestrial magnetism to lie chiefly inside the earth, even before nndertaking that labourions series of computations which brought to light the real state of the oeomagnetism for the first time. § 13. Disturbances in the Vertical Variations of Magnetic Force. The vertical variations of the terrestrial magnetic force treated in the last section, differ from -(;3h/R) times the respective components in all the three cases. The magnitudes of the dif- ferences are greater than what can be accounted for l)y observa- tional errors, being much larger than the quantities concerned in the determination of the vertical current ; and their distribu- tion is more uniform than those of the current in each country. Any one by taking observations at a dozen of well selected stations will reveal the fact if the same line of calculation be fol- lowed ; as is suggested by the general resemblance of results obtained from observations of three points in Europe with those obtained from complete surveys in the two other countries. These are no doubt due to the existence of higher harmonics in the sense of that expansion. From a physical point of view the irrea-uhirities in the surface crust of the earth, as observed in the upheavals of continents and depressions of ocean beds, 142 A^ TAXAKADATE. may naturally be expected to cause anomalies in the distribution of magnetic force, as was already remarked by many. We may suppose with v. Bezold, Leyst and others, the terrestrial magnetic force observed at a place to consist of the average effect of all the magnetised parts superposed with ano- malies of comparatively large extent, which again can be sub- divided into mean anomalies of less extent superposed with smaller. In this respect the differences above spoken of may be called variatiowd anomalies, understanding thereby nothing more than the results of numerical operations on the observed data conducted as above. Disturbance due to a Simple Source. In order to see roughly what sort of disturbances in the vertical variation of magnetic force is lilcely to be met with, take as the disturbing source a simple positive pole of strength ?/?, placed inside a sphere representing the earth. In Fig. 5, let C be its center, M the position of the source, P any point on the surface ; and put Fig. 5. CM=r MPC = c=the zenith distance of the direction of the force at P ; and CP = ?,= the variable radius vector through P (positive outward) which is to be made equal to the mean radius R, after performing differentiation. As no restriction is laid upon the value of r, the result can also be applied to the case when the source is above by making r greater than R, and paying due regard to the signs of the trigonometrical functions. MAGNETIC SURVEY OF JAPAN FOR THE EPOCH 1895.0. 143 The vertical and horizontal forces at P will be /J = rr-COSC H' = „ sine with the geometrical relations >(1) % — r cosO co?c = - r sin^ sinc = \^) tr = v' + ;ï- — 2rz gos6 or = (s - r)- + Arz sin--^- for numerical work Z' and H' denoting the vertical and horizontal components ; the latter can again be resolved along any directions in the tangent plane. Remembering that ()n 1 f)c sine — ' - = cosr and — — = — — - f)% UZ {) the vertical variations of those forces are 9Z' m = ^^(2cos"r — sin-c) = — ^SlQC cose UZ [f >(3) or in terms of d dz ßH/ 3m rs'mdiU-rcosd) >(4) dz (' P- 144 A. TANAKADATE. The Vertical Force Z is Maximum at 6=0 i.e. epicenter and Minimum at 6 = - i.e. antipode. When the source is above the level, the sense of the force is IT versed near the place directly below it, which we may now call subcenter ; while on the antipode side the sign remains unchanged. The surface is thus divided into two regions of positive and negative vertical forces by the nodal circle 6 = cos-^A (.■>) within the limit llsitive region along the circle <*=cos-(2R-^j-) (0) within the limit Pi< r <2E . It beo-ins with 0 at the lower limit and ends with - at the higher. The Horizonlal Force H 'vanishes always at 0 = 0 and t: whether the source is inside or outside the sphere, being Maximum at ^=cos-4(y(^ J. + J^y_.^-|.) (7) 0— ^) j R- + T" — 2rR[sin ip sin ^„ 4- cos ^ cos (p^^ cos(>i — 4)] ( ^ K9) where /« and ^0 are the longitude and latitude of the epi- or sub- center, or pericenter which we substitute for the two words. The North Component X' vanishes along the nodal line cos(>^-^)tg^ = tg^o It is the locus of points where the circles of equal horizontal force touch the meridian arcs, and consists of a pair of spherical ellipses, one through the pericenter and its nearest geodetic 146 A. TANAKADATE. Fk. 6 pole, and tlie other through the antipode and its nearest pole. Their form is independent of the depth or height of the source, being determined solely by the co-ordinates of the pericenter. When the pericenter is close to either of the poles, they are nearly circles which gradually flatten until they coincide with the equator and the meridian, when the source comes to the plane of the equator. Inside both of those ellipses, the force X' is positive and in the irre- gular zone between them negative. Fig. 6 is tlie stereographie projection of those curves for the intervals of 15° in the values of (14) ,/ 9 T> I ■> (above + Ö = ain-y_:l -Ell _ sill- V-o- source) and ^-^-siii-y|- A_,iii-iyi- This is possible for all positive values of r within J 'A^Yx{-^.^V^:}OV.) < r i III 68 .003 3 .047 )> IV 109 .013 35 .184 M V 107 .012 33 .110 5) III 62 .002 — I .003 }) IV 122 .015 35 493 >> V 117 .Oil 33 .544 in >) IV 131 .021 35 2.747 III }) V 124 .013 33 .662 TV JJ V 81 .000 28 .050 Meau 116°^ W. 34?o N. Those coordinates have very different weights depending npon tlic angles at which the circles cross each other, and upon the probable errors of the azimuths. Supposing the latter to increase with the distance from the middle of the country, as already discussed under the mean isomagnetics, it is taken to be 1 for the point III, 2 for II and IV, and 3 for I and V ; and the weight of the point of intersection of any two circles is taken inversely proportional to the sum of squares of their azimuth errors and directly as the square of the sine of the angle at which they cross each other. The weights of the longitude and latitude are resolved parts of the weights so found. There was no apprecial)le improvements by restoring the last figures of those coefficients which were cut off in the table above * To draw tliose circles on the gh)be through the points, tlie rotation axis was inclined to the horizon circle at an angle sin-i (cos -^ sin A) and liy rotating the globe the point )s brought to tlie plane of the horizon circle which is then the circle required, 162 A. TANAKADATE. as uncertain : undoubtedly tlie very crude nature of the result is due both to noncentrobaric distribution, and probably more to the slenderness of tlie data. Fig. 11. Fig. 11 is the reproduction of those arcs, from which we see that, notwithstanding the widely scattered distribution of the points of intersections, the arcs all pass through the region with- in a few degrees of the mean co-ordinate, apparently showing the feasibility of the assumption. The angular distances of the five points from this mean point of intersection, or the values of ß are I. on or) II. 19.°7 III. 17.°G IV. 14.°."3 V. 12.°3 The point of no vertical variation is about 20.°ö by interpolation. This excludes the possibility of the point l:)eing an antijiode by the second of (14) which shows that there can be no such circle within 01°-] of that point, so that the position of the image must be given by either MAGNETIC SUEVEY OF JAPAN FOR THE EPOCH 1895.0. 163 >■= /4 -^-— -?-____= .844 K or a depth of about 91>2 kilom. if the point be an epicentei'. ^^' '' — a/ '•> • , - 1 or? — o,^ o-, =1.453 E ^ 3 sm (.j4.°7— 20.°.)) or a height of about 2890 kih^m. if the point be a subcenter. Taking tlie latter vahie, Ave are wholly within the nodal circle of no vertical force which will be about 46.°5 from the pericenter, and therefore the horizontal force H' must be of the same sign as its vertical variation, that is, the upward decrease of the west components found in the variational anomalies must be looked upon as upward increase of eastward forces diverging from the pericenter, and consequently the image must be positive. This contradicts however the observed positive values of the varia- tions of the vertical component on the west and its negative value on the east. The image must therefore be below the surface and negative in sign, and the horizontal force H' must be considered as converging toward the point, that is negative calculated in the sense of increasing 0, and its vertical variation positive ; or practically there nuist be an upward increase of eastward force, or decrease of westward force which is just what is found. We may next find the zenith distances c of the forces from (o) by eliminating 7n and /', thus, 2 (. p èVl + i/ 3 2) being the ratio — g— /-^7-, the sign of the second term and the value of n depending upon r and 6. Confining the inverse sines within the first quadrant, these are 164 A. ÏANAKADATE. within 0-3cos-i-ri0'"=~-^^^ ^'^'^' ^^"^^'^• Fig. 13 gives the residual intensities of the vertical and horizontal components of the terrestrial magnetic field after deduct- ing those due to the mean magnetization, or what corresponds to ]\rAGXETrC SUEVEY OF JAPAN FOR THE EPOCH 1S9.").0. 107 Fig. 13. The Eirtli Magnetic Field after deducting tlie Field due to the Mean j\lao;netization 188.J. Full lines show eqiuil residual upward magnetic force-, and dotted lines 'those of down- ward forces, iigures indicate intensity in 1000 y, or, .01 C.G.S. unit-;, the arrow lines masrnitnde and direction of the residual horizontal forces. tlie distribution represented by the second and higher harmonics in Gaussian expansion. It is reconstructed from Bauer's reduc- tion with slight modifications as to the convension of representing tliose magnitudes.'" We observe in this maj^, a center of attraction not far from the epicenter now found. Bauer gives the position of this point, Longitude llO'^E., Latitude 35°N. and the intensity of the residual vertical field —.139 C.G.S. units {I.e. downward). The accidental agreement of these results, however, should not be looked upon as showing any possible existence of such a source. If this were really the case, there must be large variational anomalies in middle of China. liecent observations at a few points near this region by Sinzyö, Otani and Yamagawa give no indication of such : — * Terrestrial Magnetism Vol. IV p. 44, 108 A. TAN AK A DATE. Hongkong 114'" lO.T) 22° 1S.'2 36837' -207 Zikawei 121° 2."):8 31° ll.'Ö 32908'' Hankow 114° 17:5 30° 35:5 33922" Sjasi 112° 14(8 30° 18!! 34112^ which give approximately at ;. = 116.°3 ^=28.°0 -;r- = — 1/.8 -„-= — 1.4 -;r- =16. 2 per kilom. dz oz dz ^ (3h/R)X = -16. 3 (3h/R)Y=-0. 2 (3h/R)Z=14. 1 Y Z -207^ -22342^ 1354^ -33644^' 716' -33737'^ 246'^ -33673^' sx\ , . ny , „ fiZ' wliilo those due to the image m = -AAlx\0'', o = IlSO kilom, ^ = G,° give 9X' T. f)Y' OZ' -^- = - 10. ' 6, -. = 0.0, -V = + 1 1 . ' 5 per kilom. dz ' Oz ' Oz ' differing from the ol)served vahies by more than five times. Taking the second supposition, that the distribution is re- presented by varying image, we see that it is nearly proportional to the cube of the distance /> : — I. II. III. IV. V. Mean. 711 ,=-1.96 -1.26 -1.24 -1.62 -1.75 -1..57xlO-i» C.G.R. /'■ This makes m at the point / = 116'.°3E. ^-=.28°N. -1.57 X 10-"'x (1.18)"x 10-' = -2..")S x 10'^ C.G.S and the variational anomalies nX' -' rïV ■' i)'L' f)'; 9,i bz * Tökj'ö Sngaku-buturigakkwai Jlokoku Vol. II. p. 4