come every obstacle, and take delight in an attainment of such practical utility. To do more than devote a few pages, in order to explain in a familiar manner the principle upon which the longitude is obtained by lunar observation, would be stepping beyond the proper limits of a book on military surveying. I must, therefore, refer the student to such works as Thomson's Horary and Lunar Tables, Norie's, Riddle's, Mackay's, and other treatises on navigation, for full instructions on the longitude, as also for various astronomical problems, lunar tables, and examples in extenso of the method of working out "lunars." I may, likewise, mention the tables of the Rev. J. Cape, which were published for use along with the "Nautical Almanac," and are both convenient and portable. It may be added, that the necessary tables for working out astronomical observations have been brought to great perfection. Such plain rules, also, are given in some of the best treatises on navigation, that any one tolerably versed in arithmetic will find no difficulty in the computations. MILITARY RECONNOISSANCE. GENERAL OBSERVATIONS HEADS OF INSTRUCTION FOR RECONNOISSANCE, WITH EXPLANATORY REMARKS-PRECAUTIONS DURING A MARCH-FORMS OF REPORTS. WHEN the operations of a campaign are carried on in a country with whose nature, features, and resources a commander is unacquainted, his situation may be compared with that of a man groping his way in darkness: but, if, on the contrary, he possess an accurate knowledge of the surface over which he has to operate, he may act with a boldness and decision that will often ensure success. If the theatre of war be in a semi-barbarous country, the accounts of observing travellers and intelligent natives will often prove of essential service; but if it lie in any country of Europe, the maps and statistical reports, published by authority, will always afford much useful information in either case, a more particular knowledge, as, for instance, such as relates to the nature of the mountains, rivers, roads, woods, towns, villages, military positions, &c., can only be acquired from personal examination by active and intelligent officers. The process by which this examination is conducted, and the requisite information collected, is termed Military Reconnoissance. This important duty belongs especially to the department of the Quartermaster-General, and the officers employed in it ought to be selected in consequence of their proficiency in military surveying and drawing, as linguists, and for general intelligence and activity. As there is no kind of service more likely to bring an officer into favourable notice than an able performance of the duty of reconnoissance, it is strenuously urged on young aspirants for staff employment diligently to apply their intervals of leisure, so as to acquire due proficiency in foreign languages, military surveying, and the practice of reconnoitring and framing reports on roads, rivers, and districts of country; and they may thus profitably exercise their attention during tours of pleasure. The greatest captains of modern days, Frederick, Napoleon, and Wellington, attached the utmost importance to this service, and Napoleon especially, as we gather from the pages of Odeleben's Rélation circonstanciée de la Campagne de 1813 en Saxe; wherein he gives in detail the organization of the Bureau Topographique, under Colonel Bacler d'Albe. Under Wellington the officers of the Royal Staff Corps constituted his Bureau Topographique, and were constantly employed under the orders of the Quarter-Master General. There are now at the Horse Guards detailed plans, on a large scale, of the whole of the French territory occupied by the British army during the space of three years after the Waterloo campaign; evidencing the great Duke's attention to this important service, even at a period when he had no reason to think a renewal of hostilities probable. It is not required of a staff-officer to sketch the whole of the country that he is to reconnoitre; there is not time for this in war; but it is essential that he be perfectly competent to sketch well, to enable him to give the details of the positions, and the principal points of his reconnoissance.* In treating this subject free use has been made of the translations from the papers of the late General Bourcet, by Captain W. C. Mayne, whose well-compiled volume has been some years out of print. To abridge this operation, before proceeding to the ground, he can, from a correct map of the country, fix the situations of cities, towns, and villages, on a scale susceptible of details, and afterwards sketch in the ground, while passing over it, : The coup d'œil, or the talent of estimating distances, is of the first importance in reconnoitring; it may be acquired by constantly practising the eye to judge distances, and correcting its errors by afterwards measuring them. The position of the individual, with regard to the sun, makes a considerable difference, and it is necessary to accustom oneself to this difference, to avoid being led into errors by it when facing the sun objects appear much nearer than when the back is to it. In taking a rapid reconnoissance of mountainous country there are other deceptions to which an unpractised officer is liable: he is apt greatly to over-estimate the degree of declivity of any extensive bluff slope, even when seen in profile, and much more when seen in elevation. Again, in looking down a valley he is pretty sure to under-estimate the rapidity of descent in its longitudinal slope. Also, when standing on a mountain ridge, we are apt to think a knoll at the end of a spur is higher than our own position, though in reality the knoll is much lower. This deception is often very strong. A knowledge of fortification, if not absolutely indispensable to officers of the staff, is at least highly useful, as enabling them to report with accuracy upon any fortified places or works which may be in the district they have to reconnoitre; as also upon the facilities that open towns, villages, churches, houses, and buildings of every kind, may present for being fortified or retrenched; to mark likewise the proper sites for throwing up field-works, establishing batteries, &c., and those which from being commanded or enfiladed from points actually held by the enemy, or which they cannot be kept from occupying, would be improper for such purposes; and to calculate the time, labour, and materials required for the necessary works. It is indispensable that officers employed on a military reconnoissance should be good linguists generally, and that they should speak the language of the country in which they are to act, fluently and correctly, and write it with accuracy. Without this the information they acquire must be extremely limited, and their reports must be, at best, meagre and unsatisfactory, if not positively incorrect. If entirely ignorant of the language, they must have recourse to interpreters to obtain intelligence from the inhabitants. Questions and answers coming thus at secondhand can never be so full and satisfactory as direct ones; besides which, the interpreters may be either faithless or incompetent; or, without being either, they may not, at the moment, catch the spirit of the interrogation or reply, although they may give a literal translation of the words employed. We are all aware how much in conversation depends on emphasis and intonation, and how various and widely different are the significations of which a single sentence is susceptible, by placing the emphasis on one word or member instead of another. If but slightly acquainted with the language, they must be constantly liable to have their questions misunderstood, and themselves, in turn, to misunderstand the answers given; whence it follows that their reports can never be depended on with certainty; they may be correct, but they may be the reverse, and if so, and acted upon as correct, how fatally irreparable may be the results of their errors. It is often highly useful to an officer to speak, or at least to understand, the patois of the peasantry and lower classes in a country, to enable him to communicate freely with |