ON SCIENCE IN SCHOOL CERTIFICATE EXAMINATIONS. 489 



(First Year I., C, 2 {d)) leads to discovery that they emit oxygen. Distinction 

 between respiration and assimilation of carbon dioxide. E.xperimental dis- 

 covery (i) that both processes occur in plants growing in air, (ii) that oxygen is 

 necessary to plant life, (iii) that breathing proceeds in light and darkness, in 

 cold and warmth. 



2. Assimilation of carbon dioxide by plants ; importance in general life- 

 economy. Plant substances built up mainly of carbon, hydrogen, oxygen, and 

 nitrogen. The leaf the organ of assimilation of carbon ; microscopic differences 

 between leaves according as carbon dioxide is supplied or withheld ; starch 

 grains, the iodine test. Starch shown to contain carbon. Manufacture of 

 starch. Relation of starch to other substances in plants. Experiments on rela- 

 tion of light and darkness, cold and warmth, to assimilation ; also of seedling 

 leaves, green leaves, and variegated leaves. 



3. Assimilation of carbon dioxide as feeding. Comparison of food-processes 

 in plants and animals. Dependence of animal life on activity of the green plant. 



II. P/iysical Section. 

 A. Astronomy. 



Observations and discussions to lead up to the explanation of the (apparent) 

 annual motion of the sun. The work to be conducted as in the First Year. 



1. Revision of, and exercises upon. First Year's work — including the problem 

 of graduating a horizontal suia-dial. (Dials for permanent use may be made in 

 the handwork class, also simple altitude-meters for home observations.) 



2. The moon. The class to make a collection of drawings of the phases 

 preparatory to explanation by means of a simple model. The moon observed to 

 move among the stars. Rough measurement of interval between southings. 

 Conception of 'mean lunar day.' (Compare with First Year, II., A., 1. A 

 clock may be regulated to keep 'mean lunar time.') Lunar and calendar 

 months. Note that at the same ' lunar time ' on different dates the constellations 

 occupy a series of different positions, repeated each month. 



3. Completion of the record begun in First Year, II., A., 5 (b). At the 

 same ' solar time ' the constellations occupy a series of positions repeated each 

 year. Comparison with results in § 2 brings out that the sun moves among the 

 stars. 



4. Continuation of First Year record, II., A., 5 {a). Graph of a year's 

 observations to be drawn and compared with similar graphs of former years. 



A horizontal line across graph represents the sun's mean altitude at noon and 

 •divides the curve into two balancing segments. The sun spends half the year 

 above and half below this line (the 'celestial equator'). The equator cor- 

 responds to the plane of the sun-dial used in First Year, II., A., 4. Compila- 

 tion of a table of the sun's ' declination ' from the graph. Use of this table 

 in determining latitude at sea. 



Representation of the curve on a cylindrical projection (see footnote to First 

 Year, II., A., 2), the equator being taken as datum-line. The paper above the 

 curve is cut away and the residue bent into a cylinder. The (apparent) annual 

 path of the sun among the stars is then seen to be a plane (the ' ecliptic ') 

 inclined at 285° to the plane of the equator. Explanation of the seasons. 



5. Revision and summary of the two years' work. Distinction between the 

 ' solar,' ' lunar,' and ' sidereal ' days. Explanation in terms of (i) a diurnal 

 rotation of the earth about its axis, (ii) an annual revolution of the earth about 

 the sun, (iii) a monthly revolution of the moon about the earth. The Gregorian 

 calendar. 



B. Geology. 



Field-work arranged as part of the course in biology or geography should 

 include observations of the stratigraphical disposition of different types of 

 earth and rock (e.g. of the sand and clay on Hampstead Heath in London), 

 and of the relations thereto of the surface features (including the outflow 

 of streams). The nature and effects of river action should also be studied unless 

 taken in a previous year. 



