Agricultural Education — Examination Papers, 1881. Ixxvii 
3. Give examples of slow ami of rapid oxidation. On what cir- 
cumstance does the rusting of iron depend ? Why is iron which has 
been washed in hydrochloric acid more quickly rusted than iron not 
so treated ? Explain the production of sparks when iron is struck 
/igainst stones. 
4. Illustrate by some examples the law of multiple proportions in 
chemical combination. 
5. Give an outline of the process of making sulphuric acid. What 
weight of sulphuric acid can be made from 1 csvt. of sulphur? 
6. Give some explanation of the antiseptic action of the following 
several substances : sulphuric acid, lime, common salt ; and of the 
deodorising action of chlorine and ozone. 
7. By what means can nitrogen be made to unite chemically with 
oxygen ? In what respects does atmospheric air differ from a chemical 
compound ? 
8. Calculate how much lime is required to liberate all the ammonia 
from 1 cwt. of sal-ammoniac. If the sal-ammoniac contain 10 per 
cent, of sulphate of ammonia, what difference will that make in the 
quantity of lime required ? 
9. Explain how sugar, starch, and cellulose are related to one 
another in chemical composition, and in properties. 
10. By what tests can you detect (1) alumina, (2) silica, (3) a nitrate, 
(4) a mixture of salts of lime and magnesia ? 
N.B.— 0 : S : N : P : Ca = lG : 32 : 14 : 35-5 : 40. 
II. Agricultural Chemistry. 
Wednesday, May lltli, from 2 p.m. till 5 p.m. 
1. Point out the differences in the composition of sterile and fertile 
clay soils. 
2. In what states of combination does potash occur in soils ? On 
what soils are potash-manures likely to benefit the crops, and on what 
soils is the application of potash-salts inefficient ? 
3. What is the composition of Kainite ? How much potash is 
there in a good sample of Kainite, and how do you determine the per- 
centage of potash in it? 
4. How do you ascertain whether a soil is likely to be benefited 
by lime ? Under what circumstances is it more profitable to apply 
chalk to the land, and under what circumstances quick-lime ? 
5. Explain the fallacies involved in the so-called Humus theory, 
and at the same time point out in what way vegetable mould may 
contribute to the fertility of the soil. 
