After levelling the axis very carefully, let the object end be directed to the east, and a star looked for in the field of the transit telescope; and as a star might not be found to fall exactly on any of the vertical wires, the eye-piece should be furnished with a micrometer wire, which might be brought to bisect any star within the field. As the star continues to rise in altitude, it will evidently keep on the wire, if the axis of the instrument be in the true meridian; but if the star recedes from the wire in the progress of rising, the axis will require adjustment in azimuth, which is readily effected. Thus the transit telescope may be made to describe, with very little trouble, the equinoctial with great accuracy, especially if two or three stars be observed from the east to the west horizon. Two distant marks in the true east and west points of the horizon may also be set up; while the axis telescope, which must point at the same time to the north or south mark, will enable us to set up a distant one in the true meridian; and by reversing the axis, another mark may be set in the true meridian, in the opposite direction to the former; and thus four marks will be obtained in the true cardinal points of the horizon. The temporary piers may then be removed, and east and west piers substituted, on which the instrument may be placed, and brought by the aid of the meridian mark as nearly into the true meridian as mechanical means can effect. Should the instrument be furnished with an iron stand, or any stand capable of moving in azimuth, the temporary piers are not required. I may remark, that the axis telescope would be of great use in other respects, viz., for examining the form of the pivots, for establishing the transit in the meridian by means of an east or west mark, when local circumstances do not allow of one to the north or south, and, finally, for placing the portable transit exactly and at once in the prime vertical, which is required for Bessel's mode of finding the latitude by the transit. I propose, in some following number, to give the demonstration of this most accurate mode of finding the latitude by a portable instrument. III. ON THE ORGANIZATION OF THE CREWS OF THE FRENCH MARINE. From the Annales Maritimes. In consequence of the mode of manning ships in the French navy, as established in 1829, not being found to work well, M. Le Comte de Rigny, Minister de Marine, suggested various alterations, which were approved by an Ordonnance du Roi, bearing date 1st of March, 1832; the chief of these alterations, and a table shewing the composition of the crews of the French marine, we have extracted from the Annales Maritimes, feeling assured, they will interest many of our readers. 1st. The whole corps marine will continue to be divided into five divisions, as before-two being of the first class, and three of the second division. eomprising a force of 120 permanent companies of 103 each, or 12,360 men. 2d. Each division will be composed of superior officers (ètatmajor), and petty officers (petit ètat-major). Of as many permanent companies of 103 men each, as indicated in the following table. Of provisional companies. Of a company of boys. After enumerating various articles of local and o. minor importance, the 18th article provides That at each division there shall be a school for elementary mathematics, applicable to navigation; for the outlines of drawing; for reading, writing, and arithmetic; for fencing and swiming; for the instruction of petty officers, &c. gratis. Of the permanent companies, we are told, that each will be divided into two sections of 52 and 51 respectively; the petty officers will be subdivided into a stationary and sea-going party; the provisional companies will be of two sorts, one of 160 men, composed of volunteers and recruits from the departments; the other, which will vary in force according to circumstances, will be composed of sailors raised by the inscription maritime. The company of boys will consist of 192 in number, admitted from twelve to fourteen years of age; and, after having served to the age of sixteen, will, if they wish it, be entitled to the rating of apprentis marins. Another great change in the command of ships is, the admission of marine artillery as part complement, at the rate of twenty-four men to each first-rate ship. The ordonnance farther gives special instructions for the constant practice of the sailors at the guns while on shore, as well as embarked, and a scale of rewards is instituted, which cannot fail to stimulate men to exertion. Thus, when a ship is ordered to be commissioned, the Minister of Marine appoints the captain and other officers, not attached to companies; orders the maritime Préfet at the division, to embark so many of the permanent companies, so many of the provisional, and a certain number of boys; thus a ship is manned in twentyfour-hours after the order is issued, which, in emergencies, must more than counterbalance the disadvantage of a captain not being allowed to select his own crew. A first-rate of 126 guns in the French navy has 1089 men; 900 is the complement of a British first-rate. NO. 11.-VOL. II. The "Fourrier" has charge of all writings and accounts, and answers to Captain's Clerk, in the British Service. |