acts (ship upright) as it would on shore clear of the influence of iron; and I have no hesitation in saying that but for the use of these magnets we could not have steered the ship by this compass at all; doubtless this compass was badly placed, but it was as far forward as the man could see to steer by it. Surely then, instead of deprecating the value of compass compensation, we, as seamen, ought rather to be grateful to such men as Airy for discovering the system; and to Towson, Smith, Rundell, Evans, and Rosser for their endeavours to bring its rules so plainly and clearly before us.

With W. P. I hold that sufficient care is very often not shown by compass adjusters in selecting the position of the standard compass; and this is especially the case on board vessels built head north or south, or near these points; but if these men shirk their duty sometimes—in many cases it is not their fault, for very often they have not the time allowed them to do their work properly-and the standard compass is badly placed by them, it still remains the shipmaster's duty during the voyage to seek a better position for it-that is, the place where it will show the least amount of deviation-always taking care that such position is not near to vertical iron of any description.

When masters of iron ships look more into these things for themselves, we shall have fewer vessels arriving in Australian ports with their magnets still in the position in which they were originally placed by the adjuster in England, and their compasses either considerably over, or under compensated, according to the position in which the vessel may have been built,-while the masters growl at the compasses and wonder why it is that they are either so sluggish or so erratic in their movements that they can scarcely steer by them; they either do not know, or they forget, that in this part of the world, on the south and S.E. coasts of Australia, we are at the magnetic antipodes of England, having the south dip at 66° to 68° against 68° north dip at London.

Newcastle, N.S.W.,

September 9th, 1878.

MARSHALL SMITH,

Master Extra.

[We are always pleased to receive such intelligent communications from our correspondents; we are also glad to see

that the compass and its deviations are receiving a much greater amount of attention than formerly, and this notwithstanding the defectiveness of the examinations on the subject. As regards compass adjusters not placing the standard compass, or any other compass, in the best possible position, we fear they have little to do with it; the deck arrangements are settled in the builder's office, the builder (by contract) finds the compass, he has it fixed in the prearranged part of the ship, and the compass adjuster is then called upon to fulfil his office as best he can, without disturbing the order of things. This system is not the right one, and we suspect that much of the ill-fame attaching to the compass has arisen from this mode of proceeding. We also hear that, compass-adjusting being voted a nuisance by shipowners, brokers, pilots, tugmasters, &c., ships are, if possible, recklessly dispatched without the attention the compasses should have.-ED. N.M.]

TONNAGE OF DANISH VESSELS.

E have received a copy of an exceedingly wellgot-up and clear book on the subject of Tonnage,

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issued by the Department in Copenhagen which

has to perform most of the duties there performed by the Marine Department of the Board of Trade in London; and we cannot speak in terms too high of the completeness, care, and accuracy with which the Danish officer has performed the very difficult task allotted to him in the preparation of his valuable work. The Moorsom system is, as our readers know, the system on which all tonnage measurement is founded throughout the world. In the United States of America that system is adopted in its most simple and complete form. It includes the entire gross measurement of the ship, and no deduction whatever is allowed for engine room or crew space. This one practical fact is a complete answer to the theoretical views expressed in this country that the system of gross tonnage is impossible, or if possible, is unjust. The truth is, the British shipowner, and the

shipowner in other European countries, following the lead of England in order to encourage steamers, induced their legislatures to deduct space for propelling power, and thus adopt a lower tonnage for steamers than for sailing vessels. There is no justice and no principle in such a deduction, and it is only because the steam shipping interest obtained the concession (when steam was young, and, it was thought, needed undue encouragement) and have been allowed to retain it so long, and because dock dues are levied, to a great extent, without taking "time" into consideration, that the steam shipowners cling to their exemptions. No one can say that light dues should not be levied on the gross tonnage, for lighthouses are of service to the whole ship, to that containing engines, and boilers, and coal, as well as to that containing cargo. However this may be, the United States alone keep to the system of gross tonnage pure and simple, while the European powers "favour" the steamship to the prejudice of the sailing ship, by allowing deductions for propelling power.

The whole difficulty of the tonnage arises out of the method by which the deductions are to be allowed. The injustice of allowing a deduction at all remains; but, assuming that that injustice will continue to exist at any rate for a time, the European Powers have agreed in the case of steamers using the Suez Canal and the Danube to certain rules whereby the deductions (though wrong in principle) shall be made in the same manner in all ships; and have agreed as amongst themselves, and in order to obviate remeasurement in the ports of each other country to a set of rules for deduction which, though not actually identical, are so nearly identical as to be practically alike. The method of arriving at these deductions in Danish ships is fully explained in the book before us; but before we refer to it we may explain, for the information of our non-professional readers, that the register ton is 100 cubic feet of space, and is not a measure of weight, and that the gross tonnage of decked British ships includes the measurement of the following spaces:

(a.) The space under the second deck from below, or the upper deck if there is only one deck.

(b.) The spaces between all decks above the second deck.

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(c.) The permanent spaces, if any, on or above the uppermost deck of the ship (whether she has one or more than one deck) which are closed in so as to be available for stores, crew, passengers or cargo, other than deck cargo: (d.) All uncovered spaces on deck occupied on any voyage by

cargo.

The tonnage of the spaces included in a, b, and c above are the gross register tonnage as stated in the certificate of registry; whilst d, the tonnage of the space occupied by deck cargo, is not stated in the certificate of registry, but is ascertained every voyage. The spaces altogether disregarded in measurement of British ships, and therefore not even included in the gross tonnage, are (1.) Spaces on the upper side of the uppermost deck, which, though they may be covered over, are not inclosed so as to be available for stores, crew, cargo, or passengers.* * (2.) Spaces on deck or above the tonnage deck, cased in for air, light, ventilation, or mere access to engine and boiler space, or to cabins.

(3.) Spaces on deck, inclosed to cover boilers and engines, merely used for weighing anchor, hauling and furling sails, pumping holds, distilling fresh water, &c., totally unconnected with the propelling power and not used for stores. (4.) Privy accommodation for the use of the crew.

(5.) Hatchways above deck when they do not exceed one-half per cent. of the gross tonnage.

The spaces included in the gross tonnage and afterwards deducted therefrom are

(a.) Certified berthing accommodation for sole use of the crew

when it is properly constructed, lighted, ventilated, drained, and shut off from odours frombilge water or cargo, and is not used for cargo stores or anything else. This provision, which is a piece of special legislation, is entirely with a view to the health and comfort of the crews of ships.

*If they merely shelter deck passengers, the Board of Trade have power to exempt them specially.

(b.) Mess-room, or mess-rooms, solely for the crew.

(c.) Bath-rooms solely for the crew.

The deduction for engine-room is governed by the following Rules:

"(a.) To be rateable in ordinary Steamers. As regards ships propelled by paddle-wheels, in which the tonnage of the space. solely occupied by and necessary for the proper working of the boilers and machinery is above twenty per cent. and under thirty per cent. of the gross tonnage of the ship, such deduction shall be thirty-seven one-hundredths of such gross tonnage; and in ships propelled by screws in which the tonnage of such space is above thirteen per cent. and under twenty per cent. of such gross tonnage, such deduction shall be thirty-two one-hundredths of such gross tonnage.

"(b.) May be measured where the space is unusually large or small. As regards all other ships, the deduction shall, if the Commissioners of Customs and the owner both agree thereto, be estimated in the same manner; but either they or he may in their or his discretion require the space to be measured and the deduction estimated accordingly; and whenever such measurement is so required the deduction shall consist of the tonnage of the space actually occupied by or required to be inclosed for the proper working of the boilers and machinery, with the addition in the case of ships propelled by paddle-wheels of one half, and in the case of ships propelled by screws of three-fourths of the tonnage of such space."

The gross tonnage of decked Danish ships includes the measurement of the following spaces:

Rules respecting the space on the upper deck which is to be included in the gross tonnage, as well as the space on or under the upper deck which is to be deducted, to ascertain the net tonnage of the ship.

A.

(a.) The gross tonnage (total number of tons) of a sailing vessel is to be ascertained by adding together

1. The number of tons of the space under the tonnage deck.