cii Agricultural Education — Examination Papers, 1885. 
coal gas are available for use in agriculture ? How are these severally 
obtained, purified if necessary, subsequently used, and for wbat 
purposes ? 
3. What manurial ingredients of value does raw sewage contain ? 
Mention any process by which sewage can be purified. What are 
the chief difficulties in the way of its utilisation for agricultural 
purposes ? 
4. Describe the chemical method by which the amount of Nitrogen 
present in manures, feeding stuffs, &c., is generally determined in the 
laboratory. 
5. What are the chemical changes which take place 
(a) when limestone is burnt, 
(h) when burnt lime is exposed to the atmosphere, 
(c) when bones are converted into bone-ash, 
(d) when farm-yard manure is kept some time, 
(e) when guano is dissolved ? 
6. To what constituents do the following materials owe their 
value ? 
(a) as Foods — Linseed-cake, Cotton-cake (decorticated and 
undecorticated) — Maize-meal — -Pea-meal — Rice-meal. 
(6) as Manures — Decorticated Cotton-cake, Eape-cake, Shoddy, 
Soot, Fish Guano, Nitrate of Soda, Kainit. 
Give approximately the percentages of the valuable constituents iu 
each. 
7. From what causes may a natural supply of water be, or sub- 
soiiuently become, unfit or unsuitable for ordinary domestic pui'poses '? 
When supplied through a system of pipes, what further sources of 
danger may arise, and how can they be guarded against ? 
8. In respect of the advantages and disadvantages of a bare fallow, 
what are the chemical changes which take place in soils during such 
a fallow, and what circumstances affect the valiie of these changes ? 
II. General Chemistry. 
Wednesday, May l^th, from 10 a.m. till 1 p.m. " 
1 . Describe the chief properties of nitrogen. Explain how it may 
be obtained from atmospheric air. How can you test whether an 
organic substance contains nitrogen ? 
2. Give an account of the composition and properties of the 
substance produced when suljjhur is burnt in air. 
3. Compare the weights of nitrogen in equal weights of nitrate of 
soda and sulphate of ammonia (N : 0 : S = 14 : 16 : 32). 
4. What sort of substances can be separated from water by (1) fil- 
tration (2) distillation? How arc the properties of water affected by 
carbonic acid in sohition ? 
