mm The, mean and extreme daily Temperatures in St. Louis for forty-seven years, as calculated from daily obser- vations. Bv Dr. GEORGE ENGELMANN. The Evolution of the amepj'^an Trotting-Horse. By FRANCIS E. in J ''HER. Magnetic Survey of Missouri. 5th Annual Report. By FRANCIS E. NIPHER. ' On the Expression of Electrical Resistance in Terms of a Velocity. By FRANCIS E. NIPHER. F'rom the Trans, of the. St. Louis Acad, of Science. Vol, IV., JVo. 3. March, 1884. COMPLIMENTS OF Francis E. JSripher. Digitized by tine Internet Arciiive in 2009 witii funding from Boston Library Consortium IVIember Libraries http://www.archive.org/details/meanextremedailyOOenge -- Jnnufirv. /■'e/sriiorv. Narrh. ,„ ,^ in .r .„ ^ a ,t /I JA / e II JS X Jt '3 "^ Apri X /a IS ! 7 ' D JS M May , ' JuTie. ' July ' August. ' September ' October Naverrber ' I)prcmbc'r 90- 70- -T" 1 ... 1 LV^ , 1 ■" 1 ' 1 ^ ^ \^ ■ 1 — ^ ^^ (-J \ ■^ _\ ■ " -A 1 \-. ^ , ; X — — — — — - ^ - - — f \ — i r f ^ ^ — — — — — — — — xir — — — — — - — — — — ' t — — — - — — — ~] ' ^ s h ^ h - - - — — — - — - - - — ^=^H — — — - — — — — r~~ J _ _„ "--. — ,. ~ ! -TO , , -T' ^ — — — 1 — — — — — — — H — — — ^ — — — — — — — — V- — — _ _ — — — — T =:7 — ' — — — — — — — — — — — — — — ' — ^ \- — — ~ — — — — ' 1 — - — - — — \ ^.^ V — H ^ " fciii \ " _ 1 / 7^ " !■=>, 1 ^ \ ■ / ^ f- -^ \ /\ / ^ \ '/ !^ 1 1 vJ .\ / K — 7^>^ . Ji.1'" ^ff " 1 './ 1 / ^ / i^-l' ■y' 1 T~ __ ^ _ __ A V 1 u \ / 1,^ ''' 1 1 ^ \. 1 1 '' 1 1 '^ /T. — -- — —^ w 1 -^ - — — - - - ~- ■S. ' ti^'J: - --- r - - - - s. "" I -J _._ 1 — K / \ ^ — 1 ^ — 1 I ' s ^ 1 -H ~ /^' ^ N s \ ; /■■ ^ \ ^^>.. -"^ 1 / N r ^ : '■■■ i / \ / \! 1 K 1 ^■ 1 i\ \ -*o ■»« /^ 1 1 / \, ■\! /,o- , i .-/' J^\ i / ) \ s i >- ~y l.;- ^<^■ r 1 K . 1 /■P .s("^ .If'' 1 / \ 1 -U i ^ _/ ' .nsj-lviae'' 1 ^ -\ -.' :■> . JrW'r;..nir'- 1 y N-. 1 -N /x^ ' \/ -vne':..t«'T , i f \ 1 I 1 1 '^ \'V ^ -,1 H^d^V 1 1 1 i : / ^ S, 1 ; 1 . r. wr '. i i \ ^- t,"-; ' 1 1 ■ \, ^0- 0- 1 / 1 V 1 1 / / 1 \ ! ! y V -le j \ 1 1 \ \ / v^ 1 / , 1 ■^ \ A f \ 1 \ / \ -e /v/ ^^' N 1 / ' 1 .• <>^ ^ ' ! jL ' ii^ L\ r ■ 1 r 7t^ 35.01 i 48.18 41.59 6.0 1877 78.5 1842 1 41.6 1( ) 33.22 49.52 41.37 10.0 1856 79.5 1279 1 41.8 11 34.55 ! 49.67 42.11 7.0 1836 69.0 1848 42.0 34.4? 5 49.85 42.14 7.4 76.0 41.6 TRANS. ST. LOUIS ACAD. SCIENCE. 502 j Mean Value for each 1 Extreme Maxima and Minima observed 1 Sup- 1836-1882 '^^y- for each Day 3f the Year. | posed Min. Max. Mean. Min. 11.5 Year. Max. Year. Mean Mar 12 34.82 50.86 42.84 1836, 1857 71.0 1839, 1861 : 42.2 13 U.2i 50.64 42.44 5.0 1867 75.0 1850 1 42.4 14 34.51 50.55 42.53 j 1.0 ti 76.5 1875 42.5 15 33.87 48.89 41.38 7.5 1870 80.5 1854 42.6 16 34.14 50.03 42.08 9.0 1843 77.5 1868 42.8 34.3150.19 42.25 6.8 76.1 42.5 17 33.49 52.07 42.78 10.5 1879 . 79.0 1842 43.0 18 34.86 52.32 43.59 15.0 (< 84.0 II 43.5 19 36.09 54.82 45.45 18.5 1875 84.0 II 44.0 20 36.91 52.52 44.71 14.0 1855 84.0 11 44.5 21 34.21 50.68 42.44 7.0 1876 76.0 1878 44.8 35.11 52.48 43.79 13.0 81.4 43.9 22 35.56 54.04 44.80 13.0 1843 76.0 1857 45.0 23 37.09 55.48 46.28 7.5 II 82.5 1868 45.2 24 36.90 54.30 45.60 1 12.0 11 83.0 1842 i 45.4 25 37.21 53.76 45.48 1 13.0 11 82.5 1852 45.6 26 37.69 54.92 46.30 ! 13.5 1873 78.5 1838 46.0 36.89 54.50 45.69 11.8 80.5 ' 45.4 27 39.16 56.81 47.98 23.5 1850 85.0 1838 i 46.5 28 39.77 57.31 48.54 18.0 1855 83.5 1879 i 47.0 29 40.42 58.31 49.36 23.5 1876 86.0 1842 47.5 30 41.07 57.91 49.49 28.0 Mean "Values for each Extreme Maxima an d Minima observed 1 Sup- 1836-1882 Day. on each Day of the Year. | posed true Min. Max. Mean. Min. Year. Max. Year. Mean Sept. 8 64.48 83.47 73.97 49.5 1849 99.5 1854 73.0 9! 63.79 80.63 72.21 50.0 1847, 1869 93.5 1841 72.0 10 62.r>9 79.95 71.27 46.5 1880 96.5 1842 71.0 11 61.01 78.90 69.95 47.5 1878 94.0 " 1 70.2 12 60.69 , 77.79 69.24 46.0 1839, 1878 92.0 1865 70.0 62.51 80.15 71.33 47.9 95.1 71.2 13 60.27 I 77.85 69.06 47.0 1839, 1878 93.0 1851, 1864 70.0 14 60.37 79.16 69.76 43.5 1873 93.0 1846 69.5 15 60.51 77.88 69.19 47.5 1880 88.0 1849, 1862 ! 69.0 16 60.76 79.34 70.05 47.0 1842 91.5 1857 69.0 17 60.54 1 77.72 69.13 40.5 1868 93.0 1843, 1857 68.5 60.49 78.39 69.44 45.1 91.7 69.2 18 60.08 78.29 69.18 42.0 1863 92.5 1867 68.0 19 57.74 75.91 66.82 44.5 (( 92.0 u 67.0 20 55.76 73.68 64.72 39.0 1875 93.5 1881 66.0 21 55.50 73.29 64.39 | 39.5 1866 95.0 1872 1 66.0 22 55.39 73.69 64.54 ; 39.0 1875 92.0 1881 ' 65.8 56.89 74.96 65.93 40.8 93.0 66.5 23 58.17 76.82 67.49 36.0 1856 92.0 1881 65.5 24 58.15 76.23 67.19 37.0 (1 92.5 " i 65.0 25 57.09 75.37 66.23 : 42.0 1879 91.5 1850 64.8 26 54.61 73.81 64.21 j 40.0 1875 92.0 1847 64.5 27 54.87 73.82 64.34 | 41.5 1871 88.0 1854 64.3 56.58 75.21 65.89; 39.3 91.2 64.8 28 54.37 73.53 63.95 36.0 1839 90.5 1867 64.0 29 54.17 71.87 63.02 35.5 1846 93.0 1858 63.5 30 52.59 71.53 62.06 35.0 1851 90.0 a 63.0 Oct. 1 54.64 73.37 64.00 36.5 1856 87.0 1856 ! 63.0 2 54.68 73.74 64.21 i 38.5 u 91.0 1867 63.0 54.09 72.81 63.45} 36.3 90.3 63.1 3 54.52 73.55 64.03 33.0 1840 89.0 1872 62.5 4i 52.29 70.59 61.44 31.0 1836 88.5 (( 62.0 5 52.18 70.36 61.27 34.0 a 88.0 1879 1 61.5 6 52.52 70.03 61.27 34.0 1855 88.5 1852 ' 61.5 7 51.93 70.62 61.27 34.0 1873 87.0 1860 i 61.0 52.69 71.03 61.86 33.2 88.2 61.7 8 51.70 71.14 61.42 31.5 1868 85.0 1856 i 60.5 9 51.49 70.66 61.07 36.5 1842, 1864 87.0 1879 i 60.0 10 51.26 69.91 60.58 37.0 1849 86.0 11 59.5 11 49.98 67.14 58.56 31.5 1872 86.0 a 59.0 12 48.73 64.91 56.82 30.0 1875 87.0 a 58.5 50.63 68.75 59.69 33.1 86.2 59.5 13 45.99 65.96 55.97 29.5 1860 81.5 1879 58.0 14 1 47.20 65.24 56.22 29.5 1872 84.0 1878 • 57.5 15 I 46 88 65.82 56.35 28.0 1845 84.5 1881 • 57.0 16 47.34 65.64 56.49 27.0 1838 83.0 1842 : 56.0 17 46.80 65.42 56.11 31.0 1836, 1868 83.0 1839, 1842 55.0 46.84 65.61 56.23 29.0 83.2 56.7 18 44.64 60.55 52.59 34.5 1875 82.5 1867 54.5 19 ' 42.70 61.62 52.16 30.0 1846 84.0 1837 ! 54.0 20 42.75 62.31 52.53 24.0 1836 83.0 1843 53.5 21 1 44.60 62.47 53.53 25.0 <( 84.0 1837 53.0 22 44.15 61.47 52.81 30.0 1869 85.0 a 52.5 43.77 61.68 52.72 28.7 83.7 53.5 507 ENGE MANN — -MEAN cV EXTREME TEMPERAT'e IN ST. LOUIS. Mean Values for each Extreme Maxima an d Minima observed Sup- 1836-1882 Day. on each Day- Df the Year. ] Max. Year. posed true Min. Max. Mean. Min, Year. Mean Oct. 23 43.41 61.54 52.47 20.0 1863 79.5 1839 52.0 24 44.32 60.64 52.48 ; 20.0 u 78.0 1875 51.8 25 42.51 59.96 51.23 22.0 1841 78.5 1882 51.6 26 43.64 60.56 52.10 21.5 1862 81.5 1874 51.4 27 42.15 61.11 51.63 26.0 1869 81.5 1870 51.0 43.20 60.76 51.98 21.9 79.8 51.5 28 43.54 60.56 52.05 27.0 1873, 1878 80.5 1874 51.0 29 43.71 60.77 52.24 22.0 1873 81.5 1875 50.5 30 42.34 57.28 49.81 26.5 1863 81.5 1876 50.5 31 39.75 56.66 48.20 19.5 a 80.0 (f 50.0 Nov. 1 42.01 1 59.97 50.99 22.0 1873 78.0 1842, 1876 50.0 42.27 59.05 50.66 23.4 80.5 50.4 2 43.20 58.00 50.60 30.5 1848 77.0 1847 60.0 3 41.11 56.59 48.85 25.5 1879 75.5 1859 49.8 4 42.01 58.66 50.33 23.0 11 80.0 1850 49.4 5 41.23 55.70 48.46 25.0 1865 72.5 1874 49.0 6 38.91 55.29 47.10 1 23.5 1877 73.0 1874, 1878 48.5 41.2956.85 49.07 25.5 75.6 49.3 7 40.78 57.55 49.16 24.0 1856 77.0 1874 48.0 8 40.30 55.78 48.04 ' 11.0 1838 75.5 1868 47.0 9 37.43 51.88 44.66 16.0 1 1 75.0 1844 46.0 10 39.03 52.71 45.87 20.0 li 76.0 '< 45.5 11 40.23 53.53 46.88 26.5 1869 81.5 1837 45.0 39.55 54.29 46.92 19.5 7 7.0 46.3 12 36.93 51.66 44.29 1 17.0 1859 71.5 1879 44.5 13 36.66 52.82 44.74 15.0 IC 79.0 11 44.0 14 36.67 51.86 44.26 20.0 1872 71.5 1855 43.5 15 35.18 50.01 42.59 18.0 1838 72.0 1873 1 43.0 16 36.11 49.60 42.85 ! 10.0 u 69.0 1865 42.0 36.31 51.19 43.75 16.0 72.6 43.4 17 35.55 47.80 41.67 12.0 1838 69.0 1853 41.0 18 33.62 45.58 39.60 6.0 1880 72.0 (1 40.5 19 31 .60 45.03 38.31 7.5 u 71.0 II 40.0 20 32.59 45.11 38,85 9.5 1872 72.5 1837 39.5 21 33.09 : 45.84 39.46 10.5 1880 69.0 1841 39.0 33.2945.87 39.58 9.1 70.7 40.0 22 32.28 ' 45.92 39.10 6.5 1880 71.0 1843 38.5 23 32.14 43.97 38.05 9.5 1871 69.0 1867 38.0 24 29.85 41.93 35.89 5.5 I860 65.5 1850 37.8 25 29.83 : 41.92 35.87 0.0 1839 64.5 1856 37.6 26 31.25 i 44.06 37.65 14.0 II 65.0 1850 37.4 31.07 43.5637.31 7.1 67.0 ■ 37.6 27 31.44 43.22 37.33 5.0 1845 67.0 1870 i 37.0 28 31.64 44.05 37.84 — 0.5 u 72.0 1864 36.8 29 29.04 42.76 35.90 2.0 1872 76.5 II 36.4 30 28.55 42.98 35.76 6.5 1845 72.5 1837 36.0 Dec. 1 30.33 45.57 37.95 — 1.0 1. 72.5 II 36.0 30.30 43.71 36.95 2.4 72.1 36.4 2 31.06 44.95 38.00 4.0 1876 72.0 1864 35.8 3 30.61 43.00 36.80 8.0 1859 61.0 1842, 1873 35.6 4 30.75 42.18 36.46 — 2.5 1871 59.0 1877 35.4 5 29.45 41.33 35.39 2.5 (( 61.0 1879 35.2 6 29.56 41.88 35.72 3.5 1859 «)2.0 1861 35.0 30.28 42.67 36.47 3.1 63.0 35.4 ;oS TRANS. ST, LOUIS ACAD. SCIENCE. Mean Values for each Extreme Maxima an d Minima observed Sup- 1836 1882 Day. on each Day of the Year. posed true Min. "28.00 Max. 40.23 Mean. 34.11 Min. Year. Max. Year. Mean Dec. 7 —11.0 1882 63To" 1851 34.0 8 27.79 39.11 33.49 — 4.0 i( 65.0 1861 33.5 9 25.07 35.35 30.21 — 5.0 1876 74.5 (( 83.0 10 23.89 36.06 29.97 0.0 1868 68.0 K 32.5 11 28.19 37.61 32.90 —11.0 u 68.0 1873 32.0 26.59 37.67 32.13 — 6.2 67.7 33.0 12 25.54 37.15 31.34 — 0.5 1868 68.5 1877 31.8 13 26.25 36.70 31.47 ! 4.0 1865 62.5 1881 31.6 14 23.46 33.79 28.62 ; — 1.0 a 59.0 1861 31.4 15 23. .57 33.46 28.51 : — 2.5 1851 67.5 1877 31.2 16 24.29 34.83 29.56 — 0.5 i( 62.0 u 31.0 24.62 35.18 29.90 -0.1 63.9 31.4 17 25.10 36.91 31.00 — 2.5 1875 67.0 1877 : 31.0 18 25.76 38.87 32.31 1.0 1876 69.0 (1 30.8 19 26.37 38 10 32.23 0.5 1863 67.5 " 1 30.6 20 23 51 35.84 29.67 — 2.0 1871 65.0 ti 30.4 21 24.84 36.97 30.90 — 2.0 1865 66.0 '( 30.0 25.11 37.34 31.22 — 1.0 66.9 30.5 22 22.64 33.86 28.25 —14.0 1872 62.0 1877 yo.o 23 22.51 35.34 28.92 — 7.0 1870 61.0 1875 30.2 24 23.90 36.62 30.26 —19.5 1872 66.0 (1 30.5 25 25.42 37.95 31.68 —11.0 u 70.0 1867 31.0 26 25.63 38.06 31.84 — 5.0 <( 65.0 1875 31.2 24.02 36.36 30.19 —11.3 64.8 30.6 27 26.47 38.41 32.-14 — 6.0 1872 65.0 1846 31.3 28 26.34 37.80 32.07 — 6.0 1880 59.0 1862 31.5 29 25.83 37.49 31.66 —18.0 i( 64.0 1851 31.5 30 23.26 36.73 29.99 — 8.0 <( 66.0 1875 31.5 31 24.25 38.43 31. '!4 —10.5 1863 73.5 it 31.5 25.23 37.77 31.50, 1 — 9.7 65.5 1 31.5 The annexed diagram, for the construction of which I am in- debted to Dr. G. Hambach, represents the principal resuhs of these tables. The perpendicular lines divide the year into 73 periods of 5 days each, while the horizontal ones mark the de- grees. The central full-faced curve indicates the Mean Tempera- ture of the penthemeral periods of the 47 years, as actually found, while the dotted line represents the supposed real Mean Temper- ature as suggested in the last column of these tables. The upper- most curve shows the Highest Temperatures and the lowest curve the Lowest Temperatures observed in those same penthemeral periods within the s ime number of years. It will be noticed that while the points of Mean Temperature occupy the centre of each period, the Maxima and Minima do not show in the middle of the spaces, but on that one of the 5 days of the period on which they actually did occur. —■■I ■■■■■■■■■■■■■■■■■■■■■I IBUHBIIBIBillBSBnHBaiBBI&Sl ■■■■■■■■.^1 ■ ■■^■■■■■■■■■■■■■■■i ■!■■■■■■■■■■■■■■■ _ KaBHiMRBBnUBIH BBWl—IMMI 12 ■■■Mil IMBil —■■■■■■■■■■■ ■■■■HHHHIHBBHBaBi ■■■■■■■■■■■■■■HiiaB ■■■■■■ilHHHiBaHliiin ummmmmssmamammmm ■■■■■■■■■■^■■■■■■H ■■—■■■■■■■■■MB ■■■^■■■■■■■■■■HBaH IhSSHIEBIIBBII NIPHER EVOLUTION OF THE AM. TROTTING-HORSE. 509 The Etiolution of the American Trotting- Horse. '^ By Francis E. Nipher. In the American Journal of Science for April, 1883, Prof. W. H. Brewer has furnished data for the discussion of the change in speed of the American trotting-horse. His table is here repro- duced. TABLE SHOWING THE NUMBER OF HORSES UNDER THE RESPECTIVE RECORDS. Prof. Brewer states that the data for the speeds 2 130 and 2 127 are very unsatisfactory, but for all the others are reasonably correct. On taking the logarithms of all the numbers A^of horses capa- ble of trotting a mile in 5 seconds, it results that the plotted val- ues of log. A'^ for their proper dates give a straight line for each value of s. For the speeds 5 of 2 :30 and 2 127 these lines are parallel to each other, and the lines representing the remaining * Read May 7th, 18S3. :io TRANS. ST. LOUIS ACAD. SCIENCE. speeds are also parallel to each other, but the two groups are not parallel. For the first set, the lines can be represented by the equation log iV-=^' +0.0,5^, where y4' is a function of .y, and 7" is estimated in years from any -arbitrarily assumed date. For the second group. It is apparent that for the speed of 2 130 and 2 127 the values of N are too small, for the reason perhaps that in earlier years, when this was called good time, less general attention was paid to the breeding of trotters, while in later years, as this became a common speed, a constantly increasing number of horses of this grade have been used as roadsters and remained undiscovered in private hands. These plotted lines are shown in Fig. i. It is clear that the intersection of any one of these lines with the time axis determines the date when this speed may be supposed to have originated, or when N= i, and that this determination of the date, based as it is upon a number of observations running through a series of years, is much more reliable than the date when some accident- ally arranged trotting match revealed the fact that the horse capable of making this speed had already come. The dates for the origin of the speeds of 2 :i3 and 2:11 cannot yet be determined very accurately, and this fact is to be remem- bered in considering the discussion which follows. The following table gives the values of s in seconds and the dates for the origin of these speeds, determined as before ex- plained. The third column contains the change in speed per 3ear, calculated in a well known manner from alternate differ- ences in the two previous columns. ds 5. YEAR. dT 1 45 1854-0 143 1857-4 0-571 141 1861.0' 0-547 139 1864.7 0- 500 137 1869.0 O-506 13s 1872. G O-430 133 1878.3 0-476 131 188I.0 NIPHKR EVOLUTION OF THE AM. TROTTING-HORSE. 51I When the vakies of --^ are plotted with the simultaneous val- ues of s, we get a somewhat irregular series of points shown in Fig 2, and represented fairly well by the equation The constants A and B can be determined graphically with as great precision as the nature of the data will warrant. The values are found to be A = 1. 00 ^ = +0-0110. and the differential equation (i) becomes ^= — i-oo+o-oiio^ - - (2) This equation being put into the form ,_QO =0-oiio ^^^ S 9U. g it admits of direct integration as follows, n /df ■ 0 1 1 0 / 5-90.9 -^ So T on performing the indicated operations /(5— 90.9) =/(i-o_90.9) H-o-oiio 7"o_o.oiio 7; where s^ and 7^q are simultaneous values at any assumed date. Placing the initial values in a single term, we have /(5-9o.,)= c-^r - - (3) or for the primitive equation C-BT s = 90-9 + e - - (4) where e is the Naperian base. It thus appears that the limiting speed of which the trotting- horse is capable, which he will continually approximate and never reach, is 1:31. This follows from (2) by making — ^ = o, or from (3) and (4) by making T= 00 . / ds ^ Q /dT 512 TRANS. ST. LOUIS ACAD. SCIENCE. The constants B and C are best determined by taking the lo- garithms of (^_9i) for the vaiious vakies of 5, and plotting them on the time axis. These values are given in the following table : 5. 5 — 91. log (5—91) YEAR. T. 5 calc. DIFF. 1 45 54 1-732 1854-0 — 6.0 144.8 — 0.2 143 52 1. 716 IS.S7-4 — 2.6 142.9 — CI 141 50 1.699 1861.0 I.O 140.9 — Q. I '39 48 1.6S1 1864.7 --4-7 --9.0 139.2 +0.2 137 i^6 1.663 1 869 . 0 137-2 4-0.2 135 44 1-643 1872.6 --12.0 135-2 -|-0.2 133 42 1.623 1878.3 -18.3 132.6 -0.4 131 40 1.602 1881 -o — 21.0 131-4 +0.4 The constants are determined by well known graphical meth- ods, and it is thus found that the observations are represented by the equation log (.s_9i) = 1.703 - O-0046 ^' - (5) where the logarithms are common, and T is estimated in years from i860. Substituting in (4) the values of T for the dates of the above table, the values of s and their differences from the ob- served values of s have been determined and are given in the final column. These differences are seen to be greatest for the later dates, where the possible errors are known to be greatest ; but the error in 5- even here coriesponds to an error of only a year in date, which is certainly within the error of observation. From (5) it is easy to determine the date when the horse will have reached within one second of the limiting speed. Making s = 92, this value of 2" turns out to be 370 years. By the close of the present century the time of trotting a mile will be reduced to 2 :o4, and the time of 3 :oo will be reached in the year 191 2. But they indicate that the trotting-horse will finally be able to make his mile in a time not differing materially from the time of the running-horse, which is at present about 100 seconds. Whether or not the trotting-horse will finally beat the running- horse, as the present results seem to indicate, it is perhaps not possible to decide at present with the insufficient data at our command. A weighty consideration is found in the fact that a well trained trotter carries his body more steadily, or with less of rise and fall, than the racer, and this may possibly result to the NIPHER EVOLUTION OF THE AM. TROTTING-HORSE. 513 final advantage of the trotting-horse after the process of develop- ing and adjusting of his muscles and chest shall have been suffi- ciently carried on, so that the contest between the trotter and the racer shall have been reduced to a matter of muscular capacity. It is w^ell known that some herds of wild horses on the Texas plains were natural pacers, and even when pushed to the utmost, and for days together, by the best running-horses, the greater por- tion of them held to their gait. One large white pacer became widely known and his capture was often attempted, but he al- ways proved more than a match for the best horses that could be brought against him. Whatever may be said about the particular numerical results of this discussion, it is clear that the trotting-horse is very likely to reach a much higher speed than has been heretofore thought possible. Added Nov. 7, 1883. In the November number of the American Journal of Science Mr. W. H. Pickering has criticised the method of reduction used in the present paper (which had been printed from advance sheets in the July number of that journal), and has reached a very different conclusion from that reached in the present paper. Mr. Pickering thinks that it is objectionable to determine the value of — ^ by taking the alternate differences in s and 7^, and he has reduced the observations by taking differences between consecutive values in the table. In this way he gets the values of the third column in the table below. s. \ YEAR. ds 'dT' ds , dT ^^^''^ e. 145 143 141 139 ^37 135 131 1854.0 1857-4 1861.O 1864.7 1869.0 1872.6 1878.3 1881.O 0-59 0-55 0-54 0.46 0-55 0-35 0-7.5 0-59 0.56 0.54 0.51 0.49 0.46 0.44 0.0 — 0.1 0.0 -0.4 + 0.4 — 1-4 + 1.8 ds Plotting these values of ~y=r and the corresponding values of s, he then goes on to say that the points so determined may be rep- ds resented by a curve, such that the value of --tt^- increases as s dT 514 TRANS. ST. I.OUIS ACAD. SCIENCE. diminishes, and thus indicating disturbing causes not easily dis- cussed. Assuming that a straight line will represent the values, he determines the value of the constants, and finds that the line intersects the axis of ^ at a point where the value of 5 is — 25. This would mean that the limiting speed of the trotter is 25 sec- onds less than no time at all. When making his first discussion of the subject, the writer con- ds sidered the propriety of determining the value of -,„ by means of consecutive differences, and unfortunately rejected the method without even giving it a trial, for the reason that the dates iSSi.^ and 1878.3, corresponding to the values 131 and 133 of s. were very imperfectly determined. It was clear that the additional point thus secured would deserve very little weight. It was thought to diminish the irregvilarity of the line by combining these with previous and better determined dates. Mr. Pickering has not only used this method (which properly used is capable of yielding good results), but he has given equal weights to the val- ues of -7!, for all the dates in the table. This is the fatal defect which entirely vitiates the conclusion reached by him. A refer- ence to Fig. I of this paper will show that for the earlier dates from 1854.0 down to 1872.5 the graphically determined dates dif- fer from the real dates when the record was actually lowered by from one to two years. It will also be seen that the dates 1S78.3 and i88i.(, are subject to errors which may be as great as two years. After having made a preliminary examination, these dates might indeed have been "adjusted" so as to make them agree better with the others, but they now stand exactly as they did when first made and before any other work had been done. It is clear that the most weight should be given to the earlier dates. I have therefore plotted the new values of ^|r with the values of 5, and have drawn the line representing the values so as to give most weight to the best de- termined values. The equation of this line is ^ = — 1-24 +O-0 127 •^- - - - (6) From this equation the values of -^ were calculated as given in the fourth column of the last table. The fifth column, headed e, gives the time in years by which the corresponding time in- NIPHER — EVOLUTION OF THE AM. TROTTING HORSE. 515 tervals dT must be increased in order to bring Mr. Pickering's values of — ^^ into accordance with the values calculated from dT the above equation. In this case the intervals are supposed to be separately adjusted. If the later dates were simultaneously ad- justed or changed by intervals ranging from two-tenths to three- fourths of a year, the values of -^ , which Mr. Pickering pre- fers to use, would agree exactly with the values calculated from the last equation. Now it is perfectly clear that these later dates, and particularly the last two, are subject to just such errors as this. Whatever these values of -j=- may be said to prove, they cer- tainly do not prove that my results as before published are absurd, and they do not indicate a limiting speed of _ 25 seconds. If --^= o, the limiting speed of the horse is found to be 98 seconds. I desire to express my thanks to Mr. Pickering for his criti- cisms and suggestions, as he has corrected a tendency which I had begun to feel, to attach too much importance to the numeri- cal result reached ; but I maintain that his method, correctly ap- plied, gives in general, substantially, the same result as my own. It is not necessary to assert that this result is really correct if any person feels inclined to doubt it, because at present it is not pos- sible to demonstrate it more fully than has been done in the pres- ent paper. I only insist that it is not wholly unwarranted by the facts which we now know. Most horsemen seem to think that the limiting speed of the trotting-horse will be somewhere near a mile in 120 seconds. If this were true, the differential equation could hardly be a linear one. The equation ds where /& is a constant and L is the limiting speed, would how- ever be in harmony with this view. But this equation gives on integration an equation of the form V-y - Z = C—A T . . . - (8) According to this equation the horse would absolutely reach the limiting speed L in a finite time, — . Practically this may be true, as is in fact shown by my own equation (4), so that some such equation might really represent the results sufficiently rear 5l6 TRANS, ST. LOUIS ACAD. SCIENCE. for all practical purposes. But the relation is not a rational one, since it cannot be supposed that the horse will really attain his limiting speed in a finite time. After he had come within a thousandth of a second, it would take a great interval of time to compass the next millionth of a second. Furthermore, this equa- tion could not hold for values of Z" greater than 2^, as the value of s would then begin to increase according to equation (8). I therefore claim that equation (4), in all probability, represents the relation between the values o( s and T, and that the constants in the equation will be determined with greater and greater pre- cision as the data becomes more and more complete. Magnetic Survey of Missouri. Fifth Annual Report. By Francis E. Nipher. During the summer of 1882 the survey was continued under the same auspices as in the previous year. The friend who fur- nished the entire means for conducting the work enlarged upon his former bounty, and furnished the party with two fine spring- wagons designed with reference to the needs of camp life, and provided with all needed conveniences. Two paid assistants, Messrs. Joseph Cunningham and Albert Meyer, were also sent with the expedition, and Mr. Frank Ringling of the Sophomore class accompanied the expedition as volunteer assistant, paying his own expenses. The work of the summer was interfered with in a serious man- ner by the sickness of the horses, and more particularly by the horrible condition of the roads, due to heavy and long-continued rains. During the entire summer we were compelled to improve roads and fords, and to build bridges, and this frequently took up a quarter of our time during an entire week. This made it impossible to make complete observations after Aug. 7th, as we were obliged to travel every day in order to reach St. Louis with- in the time which could be devoted to the survey. After the above date, therefore, only declination observations were made, the magnetic meridian being determined from the morning elonga- NIPHER 5*'^ ANN. REP. MAGNETIC SURVEY OF xMISSOURI. 517 tion as explained in the previous report.* The true meridian was in nearly all cases obtained by pole-star observations, but the great number of cloudy nights made it necessary in some cases to observe at other times than at elongation. A description of the stations where observations were made is here given, the numbers being continued from the previous report. Station \o\ — Kirk-wood, St. Louis Co. Lat. 38° 36'; Ion. 90° 24' . In the orchard of H. W. Leffingwell, 128 feet from the street fence on the south, and 150 feet from that on the east. Polaris observation on elongation. Station 102 — Gray's Summit., Franklifi Co. Lat. 38° 29'; Ion. 40° 49'. On the Union road about half a mile to the S.W. from the railroad crossing, and in the second depression, 20 ft. from the road, and on the N.W. side. Polaris obs. on elongation. Station iot^— Newport, Franklin Co. Lat. 38° 36'; Ion. 91° 06'. In the "old town" on the summit of a small ridge, 128 ft. N.W. from the N.W. corner of the church. A large elm to the N.W. across the small water- course is said to be at, or very near, the N.W. corner of the S.E. qr. of sec. II, tp. 44, r. 2 W. Polaris obs. on elongation. Station 104 — On the farm of August Goebel, near Newport. Lat. 38° 34'; Ion. 91° 06' . The station was within a few feet of the middle point of the line dividing the E. half of the S.W. qr. from the W. half of the S.E. qr. of sec. 15, tp. 44, r. 2 W. Polaris obs. on elongation. In this imme- diate vicinity Dr. Goebel, grandfather of the present owner of the farm, had established two magnetic stations, where he made extended and care- ful observations. The original records of this work were given to the U. S. Coast Survey some years since by his son, Mr. Gert Goebel. The earlier station of Goebel is found by going from our station in a line bearing S. 93° 34'.5, E. 255 ft. and thence N. 83 ft. This station of Goebel's is 61 ft. W. and 14 ft. N. of the S.W. corner of the house of Au- gust Goebel. The observations here were made in the year 1839. The declination was 9° 21' E. The other station of Dr. Goebel was occupied in the year 1849. ^t is at the S. window of a now abandoned stone house, the N.W. corner of which is 158 ft. W. and 193 ft. S. of our station. The house is a one-story struc- ture, having the dimensions of N. and S. sides 18 ft., and E. and W. sides 24 ft. The window where his observations were made is in the middle ot the S. side. His value for declination in 18^9 was 9° 05' E. Our value determined June 22d, 1882, was 7° 36' . Station 105 — In Franklin Co. Lat. 38° 41'; Ion. 91° 20'. The sta- tion is on timber land of Elijah Ruck, 315 ft. N. and 15 E. of the well in * Trans, iv, 3, p. 454. 5l8 TRANS. ST. LOUIS ACAD. SCIENCE. front of the house of John Bedts, and about 325 ft. from the line between Franklin and Gasconade counties. The station was said to be in sec. 10, tp. 45, r. 4 W. Polaris obs. on elongation. Station ig6 — /w Gascovade Co. Lat. 38° 37'; Ion. 91° 29'. On the land belonging to Fred. Bruhns. a quarter of a mile N. and 260 ft. E. of the S.W. corner of sec. 19. tp. 45, r. 5 W. The station is on the bank of First creek. The value for declination here was very much smaller than at surrounding stations, but no error could be detected in our work. Whether the discrepancy was due to some minute local effect or not, we could not remain to determine, as sickness at home made it desirable to reach the telegraph as soon as possible. This is the only case of the kind so far reached, excepting in the Iron Mountain region. Two Polaris ob- servations were made on elongation. Station 107— /« Osage Co. Lat. 38° 28'; Ion. 91° 41'. On the land of Fritz Kaldeweiher, near the centre of the S.E. qr. of the S.W. qr. of sec. 9, tp. 43. r. 7 W. The station was 50 ft. N. and 33 ft. W. of the N.W. corner of Kaldeweiher 's house. Polaris obs. on elongation. Station ic8 — Z/w«, Osage Co. Lat. 38° 28' ; Ion. 91° 50' . Station on L'Ours creek* on the Jefferson city road, about half a mile from town. The S.E. corner of James N. Clark's yard is 72 ft. W. and 68 ft. S. of the station. Polaris obs. on elongation. Station 109— /« Crt//rtway Co. Lat. 38° 43' ; Ion. 92° 01' . On Little Auxvasse creek at the crossing of the New Bloomfield and Fulton road, about 40 rods S.W. of the N.E. corner of sec. 28, tp. 46, r. 10 W. A spring across the creek and just at the ford lies N. 65° E. 165 ft. Polaris obs. on elongation. Station no— Near Stffhen.'C Store, Boone Co. Lat. 38*^ 58' ; Ion. 92° 05'. About one half mile S. of the village. The old Fulton road is 12 ft. W. and the bank of Cedar creek is 105 ft. N. Polaris obs. on elongation. Station hi — Cetiiralia, Boone Co. Lat. 39° 13'; Ion. 92° 05'. The station was on a vacant lot 48 ft. W. of the centre of the street leading directly S. to the depot and crossing of the Chicago & Alton R.R., which is about a square and a half distant. The centre of the street to the N. is distant 77 ft. and leads E. to a flouring mill, the smokestack of which bears S. 90° 44'. 1 E. Polaris obs. on elongation. Station 112 — In Monroe Co. Lat. 39° 24'; Ion. 92° 10'. On the S. bank of the Long Branch of Salt river. The station was 150 ft. from the creek and midway between the road and the W. fence. The station is on the W. line of sec. 20, tp. 53. r. ii- W., and about 120yds. from the middle of this line. Polaris obs. on elongation. — Some years since the county surveyor of Audrain Co. called my attention to this region as showing * Named after the first (French) settler on its bunks. A postoffice ne.ir the stream was afterwards named " Loose Creek" P. O. by some poor speller, and this official name has since been applied to the stream, which appears on some maps as " Loose Creek." NIPHER 5'^'^ ANN. REP. MAGNETIC SURVEY OF MISSOURI. 519 marked local effects. The region is level prairie, and long N. and S. lines run bj compass aregreatlj and uniformly curved, showing an abnormally great easterly declination. This station and station No. 144, about 12 miles E., show an area of abnormal easterly declination. The disturbed region extends over an area of many miles. Station iiT^—Moberly, Randolph Co. Lat. 39° 26'; Ion. 92° 26'. On the fair grounds 184 ft. E. and 2S9 ft. S. of the W. entrance. Polaris obs. on elongation. Station 114 — Macon, Macon Co. Lat. 39° 46'; Ion. 92° 30'. In the stock-yard of O. S. Bearce, directly in front of his barn and 20 ft. from the Vine-st. fence. The city school-house is one square W. and one square N. Polaris obs. on elongation. Station 115 — In Macon Co. Lat. 39° 48'; Ion. 92° 37' On the farm of Isaiah Lewis, which is the N. halfof N.E. qr. of sec. 21, tp. 58, r. 15 W. The station was in front of the house, and midway between the road and the yard fence. Polaris obs. on elongation. Station 116 — Near Mercy ville, Macon Co. Lat. 39° 57'; Ion. 92° 42'. About half a mile N. of town. A corner-stone in the road, a quarter of a mile S. of the middle point of the N. line of sec. 35, tp. 60, r. 16 W., bears S. 3° 23' W. 589 ft. Polaris o-bs. on elongation. Station 117 — In Linn Co. Lat. 39° 54'; Ion. 93° 07', In the bottom of the west branch of Yellow creek. The station is within a few feet of the corner, a quarter of a mile due E. of the middle point of the E. line of sec. 22, tp. 59, r. 19 W. A large white-oak tree stands 20 ft. W. , and the east end of the bridge is 261 ft. distant. The mark used was an iron rod on the bridge, 11 ft. west of the centre of the bridge. Polaris obs. on elongation. Station 118 — Linnczus, Linn Co. Lat. 39° 51'; Ion. 93° 13'. On a vacant lot on the summit of the hill E. of the Burlington & South-western R.R. depot. The S. line of the yard of Chas. B. Purdin lies 166 ft. N., the N. line of the farm of Joel Wilkinson lies 166 ft. S., while the field to the E. across the road is 237 ft. distant. The court-house spire was used as a mark. Two polaris observations on elongation. Station 119 — Near Laclede, Linn Co. Lat. 39° 47'; Ion. 93° 17'. Station one mile W. of town, on the E. side of Muddy creek; about 350 ft. E. of the bridge and 20 ft. N. of the road centre. The station is said to be on the S E. qr. of sec. 36, tp. 58, r. 21 W. Polaris obs. on elongation. Station 120 — /« Livingston Co. Lat. 39° 38'; Ion. 93° 45' . On the farm of Wm. E. Wolfort, in the N.E. qr. of the S.E. qr. of sec. 33, tp. 56, r. 25 W. The station was in the cattle-yard 25 ft. from the road fence to the east (the road being on the section line), and 40 ft. N. of the door-yard fence. The middle line of the section is in the E. and W. road perhaps, 100 ft. N. Polaris obs. on elongation. Station 121 — Kingston, Caldwell Co. Lat. 39° 41'; Ion. 94° 04'. The station will be found by going from the S.W. corner of the court-house 520 TRANS. ST. I.OUIS ACAD. SCIENCE. square W. 1646 ft., and S. from the middle of the road 62 ft. It lies 91 ft, E. of the summit of the small ridge. Polaris obs. on elongation. Station 122 — /« Caldwell Co. -Lat. 39° 39'; Ion. 94° 11'. On land of Christian Smitt, 50 ft. W. and 212 ft. N. of the middle of sec. 29, tp. 56, r. 29 W. Polaris obs on elongation. Station i2-x,—Maysville, DeKalb Co. Lat. 39° 43'; Ion. 94° 24'. On the grounds of the public school building, 65 ft. W. and 21 ft. N. of the N.W. corner of the building. Polaris obs. on elongation. Station 124— /« DeKalb Co. Lat. 40° 01' ; Ion. 94° 23'. On land of Harvey Johnson, 50 ft. S. and 206 ft. E. of the middle of the N. line of sec. 14, tp. 60, r. 31 W. Polaris obs. on elongation. Station 125 — Albany., Getiiry Co. Lat. 40° 15'; Ion. 94° 21 ' . The station is 979 ft. E. of the N.E. corner of the court-house square and 8 ft. S., these measurements being along the streets. The station is 11 ft. W. and 8 ft. S. of the N.E. corner of lot 2, block 5, of Hundley's second addi- tion. Polaris obs. on elongation. Station 126— /« Getitry Co. Lat. 40° 16'; Ion. 94° 17'. The fence E. on the E. edge of sec. 15, tp- 63, r. 30 W., is 107 ft. distant. The fence S , which is the S. line of the N. half of the N.E. qr. of the section, is 193 ft. distant. There appears to be a double corner here. The evening-mark reading was missed, but the station was on raw prairie and the instrument was certainly not disturbed between the star observation and the morn- ing mark reading. Polaris was observed on elongation. Station 127 — Bethany, Harrisofi Co. Lat. 40° 16'; Ion. 94° 03'. On a vacant lot of Mrs. R. J. Turner, 365 ft. E. of the N.E. cornerof her house. The station is about 320 ft. S. of the N. line and 346 ft. W. of the E. line of sec. 15, tp. 63, r. 28 W. The line fence of T. B. Shearer's yard is loi ft. E. Polaris obs, on elongation. Station 128 — Farm of John Honafi, in Harrison Co. Lat. 40° 08' ; Ion. 93° 56'. The station was in the meadow, 133 ft. S. and 289 ft. W. of the N.E. corner of sec. 36, tp. 62, r. 27 W. Meridian determined by equal altitudes of the sun. Small cumulus clouds cut oft" five observations out of a series of seven. The two differed 1 ' . Station i2()— In Daviess Co. Lat. 40° 04'; Ion. 93° 53'. The station was in the road about midway between the track and the S. fence, and 334 ft. E. of the N.W. corner of the S. half of the S.W. qr. of sec. 28, tp. 61, r. 26 W. By reason of a very heavy rain which came up while the camp was being made it was impossible to get an evening-mark reading. The rain lasted until 9:15 p.m., and then a small patch of sky cleared around polaris for about half an hour, and a pole-star observation was made.l When the star-observation was made the whole hillside was covered with a sheet of water three to four inches inches in depth, which filled the trenches around the tent and ran through the tent in a torrent. The ground was however firm, and the tripod was as usual mounted firmly on NIPHER 5"' AW. REP. MAGNETIC SURVEY OF MISSOURI. 52I large stakes driven eight to ten inches into the ground. The observation was therefore deemed entirely satisfactory. At the next station on the next night an observation was made the same interval before elongation, and the difierence between the azimuth of the star and that of elongation agreed within a quarter of a minute with that at Station 129. Station 130 — Trenton^ Grufidy Co. Lat. 40°03'; Ion. 93° 39' . Sta- tion in a grove of Dr. Harris, in the east part of town. The station is found by starting at the front (S.) fence of the door-yard and measuring S. along the centre of the road 112 ft., thence E. 415 ft. Polaris obs. on elongation. Station 131 — In Grundy Co. Lat. 40° 13'; Ion. 93° 38'. Station in the road about midway between the track and theE. fence, and 150 ft. S.W. from the front gate of the farm of Faust Amick. The station is near the S.E. corner of the N.E. qr. of N.E. qr. of sec. 34, tp. 63, r. 24 W. Po- laris was observed before elongation, and its azimuth calculated as before described. Station 132 — Princeton. Mercer Co. Lat. 40° 24' ; Ion. 93° 39' . The station is at the base of the bluff, 395 ft. W. of the W. side of Lincoln st. and 563 ft. N. of the centre of Hickland st. Polaris observations were made at 9 and I2h. 30 m. Station 133 — In Putnajn Co. Lat. 40° 27'; Ion. 93° 21'. On land of Joseph Williams, about a quarter of a mile W. of the centre of sec. 7, tp, 65, r. 21 W. The station was about 20 ft. N. of the centre of the road, and 250 ft. E. of the front gate of the house of Crede Yocum. Polaris obs. on elongation. Station 134 — Iti Putnam Co. Lat. 40° 27'; Ion. 93° 21'. Station in a lane near the house of Joseph Ward, in sec. 12, tp. 65, r. 20 W. The middle stone of the S. line of the section is 1S9 ft. S. of the station. Pola. ris observed at 11 o'clock p.m. Station 135 — Unionville., Putnam Co. Lat. 40° 29'; Ion. 93° 03'. The station is on an open square 562 ft. N.W. of the W. corner of the court- house square and 150 ft. N.W. of the same. These measurements are made along the streets which lie diagonally in reference to the points of the compass. The sky was again cloudy at elongation, and polaris was observed at 9 h. 11 m. and 10 h. 46 m. Station 136 — In Sullivan Co. Lat. 40° 19'; Ion. 93° 07'. On the farm of Nathan Bankes, on the N.E. qr. of the S.E. qr. of sec. 28, tp. 64, r. 19 W. The station is in the meadow 26 ft. S. of the S.W. corner of Bankes' house and 249 ft. W. of the middle of the road. Polaris obs. on elongation. Station 137 — Milan, Sullivan Co. Lat. 40° 12' ; Ion. 93° 11'. On the common, 160 ft. S. of the S.W. corner of the public school building. Polaris obs. on elongation. 522 TKANS. ST. LOUIS ACAD. SCIENCE. Station 138 — Stickhrville, Sullivan Co. Lat. 40° 09' ; Ion. 92° 58'; Near the S.W. corner of the N.W. qr. of sec. 22, tp. 62, r. 18 W. The N. W. corner of the church bears S. 31° 15' W., and is distant 731 ft. The same corner of the church is 137 ft. S.E. of the qr. sec. corner before men- tioned. Polaris obs. not at elongation. Station 139 — Kirksville^ Adair Co. Lat. 40° 12' ; Ion. 92° 37'. In a vacant lot, owned by Dr. Hurley, on the S.W. corner of Fifth and Fill- more sts., 76 ft. from the centre of the latter and 83 ft. from the centre of the former street. The left side of the tower of the State Normal school building bears S. 69° 02'. 5 E. Polaris obs. on elongation. Station 140 — La Plata, Macon Co. Lat. 40° 00' ; Ion. 92° 34' . Sta- tion in the street about midway between the track and the N. fence. The middle, E. and W. line of sec. 7, tp. 60, r. 14 W., is 486 ft. N., and the E. line of the section is 637 ft. E. These distances were measured along the streets. The house of B. F. Bragg is on the S. side of the street, a little E. of the station. Polaris obs. on elongation. Station 141 — In Macon Co. Lat. 39° 53' ; Ion. 92° 22'. Station on Bear creek bottom, 304 ft. N. and 832 ft. E. of the middle of the S line of sec. 23, tp. 59, r. 13 W. , near Harris's farm. Some error was made in reading the verniers in the star observation. It is conjectured that the altitude was read too high by lo'. This conjecture is baesd on observa- tions at the next station, made at elongation and an equal interval after elongation, allowance being made for the change in latitude. In the magnetic determination on the morning of the 12th marked dis- turbances of the needle were observed. The declination diminished 9' between 6 and 7 o'clock. Station 142 — In Shelby Co., 3 miles S. of Shelby ville. Lat. 39° 44' ; Ion. 92° 04'. The middle stone on the N. line of sec. 5, tp. 57, r. 10 W., bears N. 4°, 50' E., and is distant 910 ft. Polaris obs. on elongation. Station 143 — In Monroe Co., on the farm of Henry Winkler, 40 ft. E. of the centre of the road, and 669 ft. N. of the S. line of sec. 35, tp. 56, r. 10 W. The road, which runs N. and S., divides the S.W. qr. of the sec- tion in halves. Polaris obs. on elongation. Station 144 — In Monroe Co. Lat. 39° 22' ; Ion. 91° 59'. On the summit of the S. bluff of Long Branch of Salt river, W. of the road, on land of B. F. Dowell. The land is in sec. 30, tp. 53, r. 9 W. The station was about 75 ft. W. of the road, which is on the E. line of the section. The Baptist church across the road is about 50 ft. farther S. than the sta- tion. These measurements were forgotten, and the distances were esti- mated the same day after having left the locality. Polaris observation on elongation. Station 145 — Montgomery City, Lat. 39° 00' ; Ion. 91° 30' . The sta- tion is 105 ft. W. of the middle (N. and S.) line of the S.E. qr. of sec. 32, tp. 49, r. 5 W., and a perpendicular laid off to the track of the Wabash- NIPHER 5^'' ANN. REP. MAGNETIC SURVEY OF MISSOURI. 523 Pacific R.R. track measures 200 ft. Passing freight trains caused the nee- dle to swing through 2'. Polaris obs. on elongation. Station 146 — Warrenton, Warren Co. Lat. 38° 46' ; Ion. 91° 08' . The station is at theW. end of town, about a mile from the station of 1881. Starting at the creek bridge W. of the court-house, the station will be found bj going along the road westwardlj 705 ft., thence southwardly at right angles to the road a distance of 45 ft. The court-house spire bears S. 79° 14.3' E. Polaris obs. on elongation. Station 147— /« St. Charles Co. Lat. 38° 43'; Ion. 90° 40'. The sta- tion is in the Booneslick road about midway between the track and the S. fence, and almost due south of O'Fallon.* The O'Fallon road is 250 ft. E. The house of D. Heald lies a few rods to the W. Polaris observation on elongation. Station 148—/// St. Louis Co. Lat. 38° 41'; Ion. 90° 21'. On the St. ■Charles rock road. The station was in a gap in the fence opposite the grounds of J. B. Lucas. From the station to the centre of the road the distance is 30 ft. From thence along the road to a point opposite the gate is 165 ft., while the distance in the opposite direction to a point opposite the S.E. corner of the Lucas grounds is 158 ft. Polaris observation on elongation. Station 149 — Near Atalissa, Muscatine Co., Iowa, on the farm of Mrs. Grace Aikins, on the N.E. qr. of the N.W. qr. of sec. 3, tp. 78, r. 3 W. The station is on the front path, exactly between the front gate and the house. This station is a mile west of station 33 in the report of i88o.t Polaris obs. Station 34 — This station was occupied in 1880, and is described in the report for that year. Polaris obs. on elongation. At six of the stations of the summer deflection determinations were made with the University magnetometer, with magnet Cg deflecting and Cj^ deflected, and these observations have been used in determining the value of P., and in calculating the mag- netic moment of Cg for the summer. The latter was sensibly constant, the observed diflerence between the extreme value observed and the mean of all being about o.^q^j, of the average moment. In the reduction of the work the magnetic moment was therefore assumed to be constant. The calculations for P and for the magnetic moment are given in the adjoining tables. * In the report for iSSo the Ion. of O'Fallon should be 99' 40'. t Station 33 is on the N.E. qr. of the N.W. qr. of sec. 2, and not N.E. qr. of N.E. qr. as was given in the report of 1 5S0. 524 TRANS. ST. LOUIS ACAD. SCIENCE. CN 00 00 <4- o w 0) § E S E h 3 1^ C/) tf -< O 000000 1+1 I++ ^1^ 00 00 00 GC 00 GO a,?; 55, a. s s '^ o \ Oi Oi ■^ Oi Oi Gi 00 CD O CO O t^ OC 05 00 CO QO -^ CD CO 00 O lO (Kl 05 00 C5 — I O -^ Tf -^ -^ O -x: lO 0:> Oi Oi Oi Gi Oi «.5 ^ o fe ^ oi oi c S S S S S S 1— 1 t^ 00 CO 1— 1 (M 1— 1 lO lO Ci l^ '-^ (M 0 00 CO CO CO CO 00 1-^ 05 0 0 CO CO CO CO -H -* a; CJ bfl CD Ttl T^ 1— 1 -^ .—1 — ^ 1—1 1 (M t^ 00 0 00 CO CD CO •^ CO Tt< CO CO 0 eg -rOO'M'OOOIMdO^ 1 CO OiOiOCO-tOOOOOO I— 1 1— lOOCOO— OOiOtO 1 —' oocr>c20000 Co ^ I- 1^ 00 -t ■ r cc I— 1 § ■^COCC-^COiO'^CC ^ bo CDCOCOCDCDCDCDCD CD OOOOOOOOOnOOGOGC O:i0iaiC:>GiO:>0i0i 02 OlOI~00»OCOOO II Ho 05CD'-t^C0C0I:^-*^- § s c^ii— i-^ioio-ti-^c; COCDCOCOCOCOCDCD be OC cyj GO 00 QC 00 CC 00 bJD 0 Oi^GiOiCiaiO'^Oi ^ --^ — ' -+ W CD 1— CO -f ''. \ ' — ' 'M -^ t^ CO 0 1 — ' be <» -~ o-i cr. oi 1 000 0 1 0 -CriOiOlOOC 0 0 02 C7j 0 0 0 0 + 0 0 01 03 CJ-.' 0 0 C i 1^ lOi— 'CD(Mt-0OCOI- 0 CO CDOCO-^Oi— lOO I— 1 1— 1 1 ++i 1 I++-+ - lOOOi—iiCOiOO-* t^ %;» COO>t^COO(M — I— 1 0 QOO^-l^t^OOOOOC do t^w lO'^lON 1-1 iH CC 1-1 N b, i-i N c JJ >, u C3 1) Q 3. ^ < ^ d 0 13 Is i4C )Uh- Mi- NIPHKR — 5*'' ANN. REP. MAGNETIC SURVEY OF MISSOURI. 525 The value of P^ as determined in the first of the tables, gives p for the value of i ^ the values P , I — ^ = 0.9946 log = 9-99765 _ ^ — 1 — I /j \2 — 0.9930 ^^^ 9*9 96 9 5 These values were used in the reduction of the deflection series made for the determination of the magnetic moment of magnet In the second table, the decrease (a) in the value of log m is determined, and it is found that for the summer of 1882, and at a temperature of 80.7, the value of {a) is '^•000,009' 20 32 or \o^m = 9.86415 + O-000,009 ^' where d is estimated in days from July 13. The value of log m was therefore considered constant during the summer. In all of the intensity determinations the time of vibration was determined by means of a Waltham watch belonging to Mr. Ringling. This watch had been cleaned just before leaving St. Louis, but it had not been rated. The error of the watch was determined, at intervals during the summer, by comparison with clock-beats from the observatory of Washington University, transmitted daily to the telegraph lines of various railways in the State. Its rate during the summer was a loss of 20 seconds per day, fluctuating however between 17 and 22 seconds. The cor- rection on the time of vibration was -(- o.qqj6 second at all the stations, the time of vibration at the stations not varying suffi- ciently to change the value of this correction. The effect of neglecting this correction altogether would be equivalent to the effect of an error of half a degree in temperature. The intensity determinations were all made with magnet Cg in the University declinometer, C j 7 being used as a deflected mag- net. The moment of inertia of Cg was obtained from the table given in the 4th report.* The values for H ?lx& not corrected for * Trans, vol. iv. No. 3, p. 468. 526 TRANS. ST. LOUIS ACAD. SCIENCE. the effect of magnetic brass-work of the magnetometer. This correction is given in the 4th report, p. 472. The observations for inclination were not very satisfactory, as the axes of the needles were both bent during the early part of the summer. The following observations for meridian, by equal altitudes of the sun, were made. The method of reduction has been ex- plained in previous reports. Sun Observations for Meridian. Station. Date. X3 0 0 6 Mean Time of Series. i. }i(A+A'). A. M. p. M. Little Auxvasse Cr. Honan's June 30 July 30 5 2 k. m. s. 9 36 58 9 38 25 A. m. s. 2 32 40 2 23 18 deg. m. 37 03.7 35 42-5 deg. m. 244 56.7 176 38.5 log A d". a. c. log cos a.c. log sin t Cor. South reads Mark reads Az. of Mark. I.67112 2.23805 0.10777 0.11660 0.21992 0.23384 4-o'.8 + 3-2 244°57'-5 176 41 .7 l80°02^0 180 01 .2 S.64°55-5E. S. 3 19.5 W. Polaris Observations for Meridian. Station. Daviess Co., Sta. 129. Amick's Princeton Ward's . . . . Unionville. Sticklerville Harris's . . . . Lat. o lo OnOO i-> as0>-'000\OrO>')0N0iO ^VD O On 00 VO 00 M 00 u^ ro fOOO \0 "~.00 lo I>.v£) Ov N 00 M N Th m t>.VO J>.w00 >OM lotoM O -^^ O "^ u-00 rooo O O O O 00 vO lo f< CT> O On lo U-) ro lo\0 ''lONt-rO'-' ON'^O '^r ^\0 vD ON^O Mr)«OM:^PJ^. ■^rOfOi-iONOON wi-cMOi-ii-ii-'i-iMi-iMMrororofOrorocorotnMrOM o O O O O lyj t^ vo U-) O tr!*o M li-jC^t^O t^N loioioo t^ >o 00 t^ O J>--*t^i:^rOMvO00 M t^t^ON^hONN N n n OOOVO OOt^N t^O O N l>.t^t^tot^i:^l>M M l>.t^rj t^O t^t^t>. s ■O D fe « 2 "a; ^"= U ■J- f* ^ (U ' ji > .;.- ^ >, • • = U NIPHER 5^*^ ANN. REP. MAGNETIC SUHVEY OF MISSOURI. 529 1) - H..E o o 000 t>.00 \0 t- LO ww^uw : 0 On ^ LO 10 • o\^oo r, 0 0 so 'I-OOVO r- fO - L1-, 0 fN M ro ro -^ '^- uo c) 10 0 r> • ') Th « OS 0\ • - vO rosOOO • 00 Os^ rn-i- >-< (M 10 On On I- !>• LO t^ 0\ CO 0 " 1^00 0 NO NO Tj- t^ - NO ON ^nO OnO — CJnO ttloO O S. Onh- ■^00 O LO t^ - NO '^ t^ONt^OO CTs -^00 00 CO \o MMi-chi — MtT) 1-11-1 (S « — t^ !>.»>• O LO (U to > O Ml tn 10 10 LO r> O ii c; lu c — U — ■ OS) v ' OOi-iroONOLo-^»->ON^i>-t^ ir^NO >o 0 10 tJ- Tt- LO Tt- 0 CO OsCO LO 1-1 00 ^0 t^ t^ t^ 0 0 NO rorOfOrOi^-^'^fOrOfOfOrO'N r» f» 1-1 m — vO 'l-'!^T^T^Tt-Tr't-•'r^■^T^Tt-■^T^•^Tl-Tf't■Tl- 0 10 LO t--.VO 0 LO (S 0 LO 0 !>. t^ ro r> 0 t^ t^>0 LO 530 TRANS. ST. LOUIS ACAD. SCIENCE. (0 > O sz o _c "o o a ■3'g 3 +J tfl c ——.- — - ^^ - , ^, H- > "^^ Tt- Th ONCO M M rj-vo lAvO l>.vO OS OVOO t^vo VO >^ O C N O vo vO ^ !>• t^vO !>• t^ t^ t^ t^CO J>- 1^ t^OO CO t>. t^OO 00 On M loO rO" ■*t^ON'^J>-i-i LO\0 Ol^-O'-'^Mt-Oi-' M N l>.\0 0\0 N Ti-rO'^tO'^l:^ t^\0 10 "*• '^ r^OO 00 O o \0 VO >0 t^ »>.\0 t^ !>. !>- 1^ t--00 t- t>. t^oO 00 t^ t^OO 00 OS 00 OsvO Os t~-VO rOOO <-i MOO -^t^i-it^w-iroN O m •- I>. OWO On\0 rovO 10 1- 0\vO -^O) >^.vO lt, u-.oO CO OS Ost^ -^ QwiociLOTi-Mro'Ocq'^tsooi-iOrODrii-iiy-.ro o t^MCO ^^ n u-,n O •^^ O 10 LT-.OO rooo O O O O 00 \0 ■^ Jr^ M t^OO t^" ro-^rot^ioiorO — so msDsO -^CO I>. 0000>-oNr«ioi>'MP< t>.vO t^t>.0 O N N «ol>-t^t>. O\i-i's«0i-ii-''-'0i-in0'-i0i-'N0roi-'>-i000 voOOOOOOOOOOOOOOOOOOOOo OsOOOOOOOOOOOOOMOOOOOOO »^00 CX)0000COCOCO0O0O0000CC0000COO0CO000OO0O0 Cr5^Ml-ll-lh«-^WWWI-l-H>Hl-ll-(H«l-llHl-lMM OS -^so ^ OVO t^LOOsOsOsrow ■^lo t(-oo m CC >-. 00 1-1 OssD rO M t^ t^sO M O OSN fOrOM O fS M rit^tort- roO LoO -^r^Loo "-tjO roroO O ►-' CH loc^ n n ro-^ o roco U-) ro O N O\00 o ThoO pO rOSO msCOOOOCOOO Ir^io 10 t^ roCO 0\C0 " PO "-o -^ r^sO sO -^Ni— (NvosO Th osoo t^O >^OCO00 M loO X>.00 O "J-'M toJr^trjM t^O t^l>- CJN rooo ThN j>.i-i t-i-H 000 MIX Tt-roOS'^r< Thw ir-.vo (siwioO'^roOOLoOrorO'^. O'-'i-'LoNDrorO'^ o rOOO 10 CO O N O 00 M ■^00 fODsO i-isOOOCOOOOOJ^-lo LO !>. roOO OsOO N fO Lo ■^ t^vo SO -^rir^oivo^ ■^ OsOO MM MHiMroMMCOMtr) Mi-ii-it-i M M NSO Osoo O 00 so 00 Lo N >-i OsOO H-i woo i-i\0 lOMVD OS MfOi-iOOOroOi-iO'-i--i-i-<>HOMOMroOi-i + i I I II !+++++! I + 1 + 1 I I I ^N M N M c> r< N OsosOsOsCTsOsOsOsOsw >-i — w '^ §)00oocooocoooco t^t^t^t^t^j^-t^t^ t^co co 00 00 00 I I I ^1 — ji ^1 I I II — ^1 ^1 ^1 ^1 — II ii I 1 ^1 II II I crj fO M 00 M 00 fOOO t^ O lo OS -"^ PO ro roOO lOCO ■^00 11 "osSO t^ J>-00 1>.\0 t~-00 00 00 00 O t^ t^OO so 00 so so i^ t>. __ -_ ri wirj OS Os-^«o "^ co t^co ■^00 m CO -^ ro "H CO -^ \D 00 rO'O fO rOOO VO m fO l^CO O ro t^ l-^ t^ f i VO CT\0 t^ -^ OMr~ f~0VO CO N 00 CO On 0\ OnOO OOOOCOCOOOCCOOOOCOOO t^OD COOOOOCO i>.t^t^t^ t^MD MD NO t>- *>• t^ ONOf- ^OvO 00 -OvOO O t--vb M 6 OwO On i-< >-o ro O O »^ J>.VO M Tt-\o MJ:^Oi-OOM^»^^'f»|-'i-iJ>-OM'* 'i-vo vO O O '- >^OvOM:-»tr"" loOO POVO OS J>-vO 00 -^00 CO CO 00 O O <■> ■^CO Ov On O CO CO r)i-irOfO""fO" MrO'-'Cirii-.rofON r- J>-T3 O Ov O 00 lo t^ LT) UTO M O ^oT! • '^ t^-vO -"0'^0V"300'-ia MOrOCNO">-ii-i3 "-03 'OOQ OOOOLoioO OCO iOOO^oOOOO ::ooo •ooo ooooroovocoooc oooovooooc ooon -ooo 00 00 00 00 >-■ r^co o(»oooo5 000000 t^co cococoS cocoooo -oooooo to C "2 fOVO ro t-» r) CO "^bW- 0\ 1--VO OOVOvOt^-P) OvO 'S- O^ >-< -^ t^vo lO Q t>. O I>-vO 00 D t^ioOst^O OvOvrOt^'N t^DOO " " " rO t^vO t- ro lo t^ "^00 rO-^-^Hwiy^csOri^LO-^rO'-'O'^fO'Oi-iroi-HVoOrO'-i'^OMf^MM ^ J>. N Tj-oo u^vor^fSVOvOvOvOOOCO — rivOJ>" t^OO "~.vO O " lo^O-^ioiot^ LorirO"-OOi':oo ^loro COt^-t^O"". ^o^^r^ro CO t^vo vO vO "^' "OOO ri r> cirii-i rO">- <-> rOfOi-ir.io O 0\ l>.vO 0'N0O000"0M"0"-'00r0'-'')0M'"it^ 'i-vO "^ -"t-OO r) m rfrO'^ts M LoroO N LOioi^-^-M i- roroio^-) rO" >00 ro— ■^O M M N ro T^t^!^ tJ-oO inuiO pJvOvOvOvOCOOO ■-' fjvo t^ t>.00 vovO O w inioThtoiot» lo M fO •- CO w-iCO J>-'*-Loro OOt^t^O'^LO'J^t^rO 00 l>.VO vO vO "1 lOOO rq M Mts-i rOMM « roPO—onn M NcorOMMi-i M 1-1 O f< •^Tj-X)0O "-' OV" •-' ro^O'^-rO'^'-i fO^oro— OV'*"" "^ t^vO VO 00 lo fOi-iOOi-iOP>0"Mi-i>-iMNr<'-iO'-iN>-ii-ii-«oOP>OOQO>-irO I + I I I I I + 1 I I I + r+ 1 I I I + 1 ++++++ 1 + 1 OvCvOvOvOvOvOvOvOnOvOvOv OvvO vCvOvOvOvOvOvOvOvOvOvOvOvOVOCOOOOO M ^J1 CnOO N t^i^iOLO-^rorOI>-0vr0f^'i-0 '^OO ro C — CO t^OO O OS ^o t^ O VO CO t^ t^ t^ t^vO 1^00 vO !>. t^vO CO vO CO t^ t^vo vO 00 t^CO X>-OD t^CO t^t^OOvO 53' * * * * *************** Ov O vO OvOvt^CO PI O 1-1 O O ■^ , O O 1-1 t^ ■-' 'o O t^OO lo Th lot-vO M ^O o >^ c c« J= U c « o lO^i ,:>l^ o ii • C 0) c es •- -^ .-. c3 J2 -c S ° 5 ;> ^ pq S w tii hj ffi c/2 ^ h-l 13 ^ K 6 w ■^ B O Si >iT3 a 0 en 532 TRANS. ST. LOUIS ACAD. SCIENCE. l>-00 00 t-- t>.^0 \0 \0 lO "^ w-)\0 ICVO lO ^O lO lO ID "^ ''^ ■+•■^"^■.\0 \OvD Low-ivO^^ LOU-, ly^LOLow-)!/-, 666666666666d66666666 0\ fO <^ Cs\D CO r^vO N t^\0 (SOO^l^^^O^<00 lOOO w rovo '-I rO Tj-oo CTn^ fO ro t^ ■^OO m On On OnOO ■<1-00 666666666666666666666 rocororocOi-iMioi-Hi-iOi-iNfONMnM'-ii-r) M N r) M M (S (N fj n "^i r> n n M M M N M M fs r> N n M n n (-1 M r« M n n D M r) M n M (S (S N 'I DvOvOOO rot^roO '-i t-^t^-^O-^i-c w i-i f^ NVOOO 1>. O >-> rr> rn -^ '^ i/-.\0 t^\0 00 OSMVO i01>.-" ioON'^CT\ VO -^ 1-1 VO ■* rOCO 00 O ro ro On roOO \0 1^.00 00 00 N OO t- t^ r^ t-^ t^CO CO CO 0\ On OnCO On«) On On On On On O On VOnOnOnOnOnOnOnOnOnOnOnONOnDnonO^nOnO t^NO VOOO MNO >-> >^LoOOO t^iow (NVO t^i-< -^00 t--.NO NO 0000 OnOOOI^'- OnOOO n "-,nO 00 rO t^ on "".CO O >^ 00 r^ t^co t^OOLri"0'~iO OnCO CTn On On On Q " O^ OnOnOnCJnOnO O OnO O O O C>On-OnOOnOnQ O On OnOnOnOnOnO u OnO O O O CTnOnOnOnOnOnO O On OnOnOnOnOnO O OnO O O O OnOnOnOnOnOnO O On Tt-vo -^D inOnoCO t^M <"» -^nO t^ t(-nO 00 CO to n lo rO'*-<"Orof^roror< rO'l-rorO-^-f-i roroiN •n mro^) OOOOOOOOOOOOOOOOOOOOO OOOOOOOOOOOOOOOQQOOOO OOOOOOOOOOOOOOOOOOOOO 6666666666666666 o c o o o NO lo rooo nO^iCOin On'^"'- ONro OnnO r^ r^co t— w On t^ t^ t^ t^ t^CO C/D ONCO ON ONCO ONCO On On On On On O On nOnOnOnOnOnOVOnOvDnOnOnOnOnOnOnOVOnOnC 1>.\0 a, lOOO NOOMi-iOMLo<^ONIOMJ>.m Ot^ LONO O O tc O ^ fe 1) ^■^ C u iJ c •- o ^ UC/3 J- i aj .= o.i: 3 iJ 53 o W O -I < c« U S > 3 o :;: ^ c - ' ' u o i::; "C >^ cs r; c o c ^£ i; (u ^ S S < mi^ o :? ^ u C.2 ANN. REP. MAGNETIC SUKVEY OF MISSOURI. 533 00 -H O ^ charged with Q units of electricity, and hence the potential of the sphere on itself between the limits r and r' is equal to the difference in its initial and final energy. If the sphere were connected with the ground, by a wire of re- sistance (/?), the radius (r) might be changed in such a manner * Read March 17th, 18S4. r — r 536 TRANS. ST. LOUIS ACAD. SCIENCE. as to preserve the potential ( F) constant. In this case a current of constant intensity would flow through the wire, and as F= — it is clear that r must change at a uniform rate, or = /'-/ - - - (3) where t' — / is the duration of the operation. Further, Q 47rrV K = -^= = 477r/j r r and V . ^^"^^^ dE=dFdr=2TT p2 dsdr= — drdo> , or V^ rr V^ B-B' =^jC/drdo>=-^ (r-r') . . (4) This is the stored energy during the operation. But the energy of the electrification at first was h r V^, and at the end is 2 r' V^, so that there has nevertheless been a diminution of energy of B — B'=~(r—r>) ... (5) It appears that, under conditions of our experiment, the sphere has less energy at the close of the experiment than at the begin- nmg by a quantity — (r — r'), while the equal energy repre. sented by the potential of the electrification on itself was added. The total energy lost by the shell was, therefore, jB = V^{r—r') - . - (6) The current in the wire was, by Ohm's law, dq_ F, ^- dt - ^ ' hence ^ ^ V and hence the energy of the current during the operation was or by (3), K' r-r' ■ _ _ R V ^'' The expressions (6) and (7) must be equal to each other, and bence Rv = x , or /? = - , where v is the constant velocity of each point in the surface of the shell during the operation. i