428 
Senior Examination Papers, 1890. 
what the volume would be if all the sides had equal slopes, and give a reason 
for your answer. 
6. A, B, C, D are four successive points, and their horizontal distances are 
as follows : — AtoB = 2 chains, A to C = 6-30 chains, A to D = 12-10 chains; when 
a spirit level is between A and B and the staff is first at A and then at B, the 
backsight reading is 6'78ft. and the foresight reading is 1*05 ft. ; similarly, 
between B and C, backsight 5 82, foresight 3'47 ; between C and D, backsight 
2 74, foresight 625. Arrange these measurements in the form of field-book 
entries, and draw a section of the ground, using for the horizontal scale 1 in. = 
2 chains, and for a vertical scale 1 in. = 10 ft. The datum line may be assumed 
to be 10 ft. below A. 
7. Explain the principle of the Vernier. 
A scale a foot long is divided into 100 equal parts ; construct a vernier for 
the scale, by means of which it can be read to thousandths of a foot. 
N.B. — By " construct" is meant, draw a line of the actual length of the 
vernier and divide it into the requisite number of equal parts. 
8. A, B, C are three points ; at A, A B bears N. 65° 30' E. ; at B, B C bears 
N. 27° 15' W. ; from A to B is 1,000 yards, and from B to C is 700 yards ; 
calculate the bearing of A C at A and verify the result by construction. 
EXAMINATION IN AGRICULTURAL ENGINEERING. 
Maximum Number op Maeks, 200. Pass Numbee, 100. 
Wednesday, May \ith,from 10 a.m. till 1 p.m. 
N.B. — Nut more than half the questions should he attempted. 
1. Suppose a brick wall 20 feet high and of uniform thickness is required 
to resist a wind-pressure of 20 lbs. per square foot acting uniformly over its 
surface ; explain how you would decide on the thickness of the wall so as to 
enable it to stand the wind-pressure safely. 
2. A handspike 12 feet long is employed to raise a stone. The fulcrum is 
placed 2 feet from the stone and a labourer presses the end of the lever down 
with a force of 120 lbs. Calculate the lifting pressure on the stone and the 
pressure on the fulcrum. 
3. Explain what is meant by " Work " and by " Horse-power," and give 
some illustrations. 
4. Explain what is meant by the " Mechanical Equivalent of Heat," what 
is its numerical value, and show how it is applied in calculating the efficiency 
of heat engines. , 
5. Explain the method of calculating the heat capable of being developed 
by a fuel the chemical composition of which is known. 
6. Describe briefly the chemical composition of the atmosphere, and the 
principal properties of ah. 
7. Explain how the column of mercury is supported in a barometer, and 
show what is the maximum height to which a pump may be expected to suck 
water. The specific gravity of mercury is 13'4. 
8. A stream of water with a fall of 15 feet is available for driving the 
machinery of a homestead. It is desired to secure a clear 12 horse-power ; how 
many gallons or cubic feet of water per minute will be required to yield the 
necessary power ? The efficiency of the motor may be taken at 60 per cent. 
9. Sketch a single-flue Cornish boiler and its setting, giving the main 
dimensions. 
10. Sketch an ordinary hemp-packed gland for a 2^-inch piston rod, and 
give the main dimensions of the parts. 
11. Describe the cycle of operations in the " Otto " gas-engine as made, for 
example, by Crossley Brothers. 
