168 REPORTS ON THE STATE OF SCIENCE.—1917. 
II. Physical Section, 
A. Astronomy. 
The following subjects should be taken in class. Further yoluntary work 
may be directed and encouraged by the School Science Club. 
1. Revision of previous work. The fundamental importance of sidereal 
time. The astronomical clock. Fixing positions of stars by right ascension 
and declination. Construction of star-charts. (In connection with these the 
use of the polar and meridional gnomonic projections may be either taught or 
applied from the geography course.) 
2. Plotting of monthly course of the moon upon a cylindrical projection 
(compare Second Year, II., A., 4), right ascensions and declinations being taken 
from ‘ Whitaker’s Almanack.’ The path of the moon thus shown to be approxi- 
mately a plane inclined to the ecliptic. 
Plotting on enlarged scale of paths of moon and sun about the times of 
new and full moon. (It is best to use the gnomonic projection, since the paths 
are then straight lines.) Conditions for eclipses. 
3. The variation in distances of sun and moon deduced from varying 
observed diameter. (Data from ‘Whitaker's Almanack.’) Perihelion and 
aphelion; perigee and apogee. The orbits of earth and moon elliptical. Calcu- 
lation of eccentricities. 
Regression of moon’s node; influence on dates of eclipses. The precession 
of the equinoxes, 
Simple theory of tides. 
4. The planets. The Ptolemaic and Copernican theories. 
The relative distances of the planets from the sun and of the moon from 
the earth. Measurements of absolute distances by parallax, transit of Venus, 
&c. Kepler’s laws. 
B. Geology. 
The following subjects may be expected to be taken during this year in 
geography lessons :— 
1. The stratigraphy of the home region. One or two lessons based on 
evidence acquired on field-excursions or reported by individual pupils, museum 
collections, &c. Thus, in London a clear idea should be given of the geology 
of the Thames basin from the northern to the southern chalk heights, the 
evidence of borings for artesian wells, &c., being examined. The probable 
geological history of the region. 
2. Extension to neighbouring regions : for example, in London to the Weald, 
Surrey, Hants, and the Isle of Wight. 
3. Outline of the geological structure of typical regions, such as Wales and 
the northern coal-fields of England. 
C. Mechanics. 
The following subjects are to be regarded as territory common to the 
courses in science and mathematics. Much (or all) of the work may be taken 
in mathematics lessons. 
1. Uniform and variable velocity (linear and angular), average velocity, 
velocity at a given moment; distance-time and speed-time graphs. 
Two cases of special importance: (i) Falling bodies and projectiles. The 
vertical distance fallen found to vary with the square of the time; hence the 
average, and therefore the final, vertical velocity must be proportional to the 
time. Value of ‘g.’ (ii) Pendulum motion. Here, since the time of swing is 
constant for small arcs, the average velocity is proportional to the amplitude. 
It follows that the velocities at all corresponding moments, including the 
moment of mean position, are proportional to the amplitude. 
2. Velocity as a vector. Relative velocity. Vectorial representation of 
changes of velocity. Utilisation of the property given in 1 (ii) to measure 
eyanees " velocity produced by collision of swinging balls (Goodwill’s ‘ Vector 
alance ’). 
