ancient volcanic (or trappean) rocks to be met with?

17. The stone of a quarry is divided by horizontal and vertical or inclined planes; what is their nature, or presumed cause? and what are they called?

18. Give some instance of a rock whose geological age and relations may be determined by the nature of the fossils it contains.

19. To what classes of the animal kingdom do the fossils called Trilobites, Terebratulæ, Encrinites, and Belemnites, respectively belong?

20. Enumerate the British stratified rocks in the order in which they were formed.

EXPERIMENTAL SCIENCES.

F. A. ABEL, Esq., F.R.S.

(Replies are not required to more than 12 questions.)

1. State the nature, composition, and chemical names, of the following well-known substances: blue vitriol, black-lead, white-lead, quartz, vermillion, pipe-clay.

2. Three vessels contain, respectively, air, oxygen, and protoxide of nitrogen (nitrous oxide). Describe the course of experiment by which you would identify the contents of each vessel.

3. Point out the difference, in composition and properties, between carbonic oxide and carbonic acid, and describe how each gas may be converted into the other.

4. When coal is burned in a stove or grate, what are the principal products of the change which it undergoes? State what is the cause of the difference noticed between a coke- and a coal-fire, and describe how coke is obtained, as a secondary product, in an important branch of manufacture.

5. Give a full description of what occurs when some fragments of charcoal are thrown on to fused saltpetre; state in what respects the results differ from those obtained on inflaming gunpowder.

6. You are provided with 500 grains of marble; how many grains of caustic or quick-lime, of hydrate of lime, or of chloride of calcium would it furnish, and how would you proceed to the production of each of these three substances?

Equivalents: calcium, 20; oxygen, 8; carbon, 6; chlorine, 35.5.

7. What is understood by the ductility, the malleability, and the tenacity of metals? Arrange the metals lead, iron, gold, silver and tin, in their proper orders, with reference to the extent to which they are malleable, ductile, and tenacious.

8. You have four small bars of the metals copper, platinum, iron and silver. Describe how you would determine their relative powers of conducting heat, and state in what order they should follow each other, as conductors.

9. State which of two helmets, the one of polished metal, the other of black felt, would be most objectionable in a hot climate, and point out what it would be desirable to provide to each helmet, in the event of its being worn in very hot weather.

10. A tube containing water, and an upright bar of metal, are both heated from below. Is there any difference in the manner in which the heat is transmitted through the liquid and the bar?

11. In certain atmospheric conditions, the surface of a sheet of water, in an exposed locality, is observed to be covered with clouds of vapour. Under what circumstances does this occur and to what do you ascribe it?

12. It is desired to raise the boiling point of some water, in an open vessel, above 212° Fahrenheit. How may this be accomplished; and how could you cause water to enter into violent ebullition at a temperature considerably below that?

13. Some caustic potassa and some nitrate of potassa are contained in two vessels. Cold water is added to each substance. Considerable heat is evolved in the one instance, while, in the other, the contents of the glass exhibit a great reduction of temperature. In which case is the latter result obtained, and how do you account for these opposite phenomena ?

14. How would you propose to decompose water by means of a voltaic battery, and what results would you obtain?

15. Could you reunite the products of that decomposition by electric agency? If so, describe the method of proceeding.

16. If, under certain conditions, I place my hand on the prime conductor of an electric machine, while it is in action, you may, in a short time, produce an electric spark by approaching a finger to some part of my body. Describe what conditions are necessary, for the attainment of this result, and account for the peculiar appearance exhibited by my hair, soon after my hand is placed upon the conductor.

17. Describe what occurs when a cloud which is positively electrified, approaches a lightning conductor.

18. Are you acquainted with any method by

which the strength of an electric current may be determined? If so, describe and explain it.

19. Give a simple illustration of the difference between electrical conduction and induction.

20. You require a Leyden jar for some experiment and have not even a glass vessel of any kind at hand. Could a sheet of glass be made subservient to your purpose ? If so, describe in what manner you would apply it.

21. State what you know with regard to electrochemical decomposition and the electro-chemical order of the elementary bodies.

22. Point out and illustrate what is understood by the neutral line, or equator, of a magnet.

23. Give an explanation of the fact, that the power of a magnet is increased, if a bar of iron is placed in contact with one of its poles.

24. Describe and explain a method of applying a voltaic current to the production of magnetic phenomena.

COMPETITIVE

EXAMINATIONS.

THE Rev. Charles J. Hughes, M.A. (Wrangler St. John's College, Cambridge), prepares twelve pupils for the above and the other Army Examinations. Mr. Hughes is assisted by a resident tutor (a Cambridge Senior Optime), and by teachers of the various branches required in the Examinations, and devotes his whole time and attention to his pupils. He has had seven years' experience in preparing for the Engineers and Artillery, and has passed upwards of 150 pupils, the majority of which were for the Scientific Branches.

At the Woolwich Examination, January 1860, Mr. Hughes passed four pupils (all he sent up), and he has also passed two or more at most of the preceding Examinations.

*** Mr. Hughes will probably have two or three vacancies shortly.

ADELAIDE LODGE,

61, FINCHLEY ROAD,

ST. JOHN'S WOOD,

N.W.

May 31st, 1860.