+-----------------------------------------------------+------------------------------+
| Mean Diurnal Inequalities for the year. |Numerical Values of resultant |
| | current. |
+----------------------+------------------------------+------------------------------+
| Greenwich. | Thorn-Berlin-Dresden. | Thorn-Berlin-Dresden. |
+--------+-------------+--------+-------+------+------+------------------------------+
| |North | East | Berlin | Thorn |North | East | Mean hourly values from |
| Hour. | to | to | to | to | to | to +-----+-------+--------+-------+
| |South | West |Dresden.|Berlin.|South | West |Year.|Winter.|Equinox.|Summer.|
| |(Mag.)|(Mag.)| | |(Ast.)|(Ast.)| | | | |
+--------+------+------+--------+-------+------+------+-----+-------+--------+-------+
| 1 | -94 | -41 | -17 | -13 | -20 | -10 | 81 | 94 | 51 | 98 |
| 2 | -68 | -24 | -6 | -13 | -9 | -11 | 84 | 115 | 39 | 97 |
| 3 | -44 | -8 | -1 | -1 | -1 | -1 | 84 | 113 | 31 | 108 |
| 4 | -18 | +9 | -20 | +15 | -17 | +17 | 101 | 94 | 58 | 127 |
| 5 | -30 | -1 | -79 | +21 | -74 | +32 | 122 | 58 | 78 | 230 |
| 6 | -63 | -33 | -139 | +5 | -136 | +26 | 148 | 80 | 139 | 225 |
| 7 | -121 | -80 | -138 | -36 | -144 | -14 | 166 | 155 | 206 | 136 |
| 8 | -175 | -123 | -7 | -98 | -28 | -92 | 203 | 152 | 185 | 271 |
| 9 | -156 | -137 | +249 | -156 | +212 | -184 | 305 | 67 | 272 | 575 |
| 10 | -43 | -77 | +540 | -184 | +494 | -254 | 557 | 232 | 628 | 811 |
| 11 | +82 | +1 | +722 | -165 | +678 | -263 | 728 | 411 | 885 | 887 |
| Noon | +207 | +66 | +673 | -107 | +642 | -200 | 675 | 441 | 848 | 735 |
| 1 | +245 | +94 | +404 | -20 | +395 | -79 | 400 | 284 | 510 | 406 |
| 2 | +205 | +113 | +35 | +55 | +46 | +47 | 98 | 68 | 103 | 125 |
| 3 | +153 | +97 | -261 | +99 | -237 | +132 | 272 | 136 | 355 | 324 |
| 4 | +159 | +108 | -397 | +114 | -368 | +167 | 404 | 218 | 503 | 492 |
| 5 | +167 | +118 | -391 | +108 | -363 | +160 | 397 | 206 | 453 | 532 |
| 6 | +125 | +95 | -311 | +96 | -287 | +137 | 319 | 176 | 333 | 446 |
| 7 | +43 | +55 | -237 | +85 | -216 | +115 | 247 | 180 | 250 | 312 |
| 8 | -22 | +4 | -191 | +74 | -173 | +98 | 201 | 207 | 217 | 181 |
| 9 | -115 | -49 | -168 | +59 | -153 | +81 | 174 | 208 | 194 | 120 |
| 10 | -138 | -74 | -135 | +40 | -125 | +58 | 138 | 155 | 149 | 111 |
| 11 | -136 | -70 | -84 | +18 | -79 | +29 | 89 | 64 | 95 | 107 |
|Midnight| -147 | -80 | -43 | -2 | -43 | +4 | 91 | 42 | 119 | 111 |
+--------+------+------+--------+-------+------+------+-----+-------+--------+-------+
It was found that the average current derived from a number of
undisturbed days on either line might be regarded as made up of a
"constant part" plus a regular diurnal inequality, the constant part
representing the algebraic mean value of the 24 hourly readings. In both
lines the constant part showed a decided alteration during the third
year--changing sign in one line--in consequence, it is believed, of
alterations made in the earth plates. The constant part was regarded as
a plate effect, and was omitted from further consideration. Table I.
shows in terms of an arbitrary unit--whose relation to that employed for
Greenwich data is unknown--the diurnal inequality in the currents along
the two lines, and the inequalities thence calculated for ideal lines in
and perpendicular to the _geographical_ meridian. Currents are regarded
as positive when directed from Berlin to Dresden and from north to
south, the opposite point of view to that adopted by Weinstein. The
table also shows the mean _numerical_ value of the resultant current
(the "constant" part being omitted) for each hour of the day, for the
year as a whole, and for winter (November to February), equinox (March,
April, September, October) and summer (May to August). There is a marked
double period in both the N.-S. and E.-W. currents. In both cases the
numerically largest currents occur from 10 A.M. to noon, the directions
then being from north to south and from west to east. The currents tend
to die out and change sign about 2 P.M., the numerical magnitude then
rising again rapidly to 4 or 5 P.M. The current in the meridian is
notably the larger. The numerical values assigned to the resultant
current are arithmetic means from the several months composing the
season in question.
7. The mean of the 24 hourly numerical values of the resultant current
for each month of the year a deducible from Weinstein's data--the unit
being the same as before--are given in Table II.