9. What is Diathermancy? Describe experiments for comparing the diathermanous properties of glass and of rock salt.

or 9. Describe Regnault's Pyrometer, and the method of using it, and of computing the required temperature.

MAGNETISM AND ELECTRICITY.

What are the dimen-
At the last visitation

10. What is a magnetic field? sions of field intensity? of the Royal Observatory, Greenwich, it was reported that the mean horizontal force of the earth's magnetism was 3.926 English units (ft. gr. sec.). Express this in C. G. S. units.

or 10. Describe the construction, principle, and use of the Bifilar magnetometer.

11. Describe and explain fully the method of determining, by means of a compass needle, the distribution of magnetism in a permanent bar magnet.

or 11. Describe and explain fully the use of the torsion balance in testing the laws of electrical 'force.

12. Describe Wheatstone's Bridge with Rheostat and slide. How is it used to determine external resistances? 100 ft. of copper wire are inserted in one arm of a bridge, and 150 cmrs. of Rheostat wire in another. The parts of the remaining arm, respectively adjacent to the former, are 71 cmrs. and 29 cmrs. in length when the slide is in such a position that no current flows through the galvanometer. The resistance of 38 cmrs. of

Rheostat wire is an ohm. What length of the wire would have a resistance of an ohm?

copper

13. Why are the opposite quadrants of a Thomson Quadrant Electrometer connected by very fine wires? Why is it easier to send a message through a land wire than through a cable? or 13. Define the "Practical Ohm," as recently determined and adopted. Describe fully the construction, principle, and use of standard resistance coils. Is it better to use coils or Rheostat in the Wheatstone's Bridge?

NATURAL PHILOSOPHY.-PART III.

Professor Andrew.

Candidates may not answer each of two alternative questions.

Candidates must shew some knowledge in each division of the paper and a satisfactory knowledge in two divisions.

DYNAMICS.

1. Illustrate the four cases of compounding parallel forces by figures, and investigate the line of action and the magnitude of the resultant.

or 1. Forces are represented in magnitude and in direction by the sides of a plane polygon taken in order. Find the resultant.

2. Describe the principle of White's Friction Brake, or any modification of it.

or 2. Describe the rough screw (1) when the nut is moveable, (2) when the nut is fixed and the step is moveable. Calculate the friction at the step, which is a plane circular disc. Give practical illustrations of the two cases.

3. Investigate expressions for the normal and tangential acceleration of a particle moving at any instant on a given curve with given velocity. or 3. Find the velocity with which a particle must be projected from the lowest point of a smooth vertical tube that it may just pass the highest point.

4. State the laws of impact. How are they experimentally verified ? Investigate the method of finding the initial velocity of rifle bullets by means of the Ballistic Pendulum, and describe the method of using the instrument.

or 4. Describe the construction, use, and principle of the unifilar torsion balance, and the method of calibrating it.

ASTRONOMY.

5. Define the Right Ascension and Declination of a point on the celestial sphere, and, briefly, the methods of determining these coordinates for a

star.

6. Describe the Zenith Sector, and the method of using it to determine latitude by means of two stars culminating on opposite sides of the zenith at a short interval, and having a small difference of zenith distance. Explain clearly the advantages of the method.

or 6. Explain fully the means adopted for determining the difference of longitude between Greenwich and Melbourne, by means of the telegraph. Why were transit observations at Port Darwin necessary?

7. Describe a Transit-circle, and mention any important differences between the old and new Transit Circles at the Melbourne Observatory.

or 7. Describe the construction, use, and principle of Hadley's Sextant. Explain the practical method of determining its index error, and the method of using it with an artificial horizon to determine the double meridian altitude of the lower limb of the sun.

8. What is meant by "Personal Equation"?

De

scribe an apparatus for determining the absolute personal equation of an observer.

or 8. Describe a method of determining, approximately, and by unaided vision, the position of the South Pole, and describe the relative positions of a Centauri, a Crucis, Sirius, Canopus, and Achernar.

HEAT AND LIGHT.

9. Define a perfect gas. Demonstrate the form of the isothermals for such a gas. Shew that in this case E

=

= p. 0

or 9. How did Hirn disprove Carnot's idea that Heat is a material substance, and that the heat taken from the source by a perfect heat-engine is equal to the heat given up to the refrigerator by the same engine?

10. Shew that in a perfect gas the ratio of E to E

is constant; or describe a method of determining the ratio by experiment.

11. Describe the construction, principle, and use of the double-mirror Heliostat.

or 11. Describe Hirn's method of determining the value of J.

12. State the law of refraction for light. Explain what is meant by "total internal reflexion," and give a practical application of the principle in the construction of the transit circle.

or 12. In one experiment of Fizeau's method of determining the velocity of light the number of teeth was 720, the wheel made 12.6 rotations per second, the distance between the two telescopes was 9,440 yards. Shew that, by this experiment, the velocity of light is 3 × 1010 C.G.S. units.

ANCIENT HISTORY.

Professor Elkington.

1. What is meant by the principle of Exogamy? How do you account for its disappearance in modern times?

2. What, in the ancient world, were the checks upon the harsh or capricious exercise of paternal authority?

E