ENGINEERING INSTRUMENTS. 84 ENGINEERS. time of two miles; while some heliotropes have been used so powerful as to be visible nearly 200 off. The term heliostat, applied by Captain Druiumond to an instrument invented by him for I he same purpose, more properly belongs to an instrument invented by 'sGravesande, consisting of an equatorial revolving on it- polar axis, so e sun. when onee accurately in the focus of pe, continues steadily tixed there. Drummond's heliostat is chiefly used in Great Britain. For full discussions and descriptions consult: ing and Leveling Instruments (London, L891); Baker, i Surveying (New York. 1892). See .Surveying. ENGINEERING SCHOOLS. See Technical I [ON. ENGINEERS, Corps of. The Corps of Engi neers of the United States Army, organized in 1802, originally consisted of one colonel, one lieu- colonel, two majors, four captains, four first and second lieutenants, and cadets; the whole number not to exceed 20. They were sta- ll Wesl Point, X. Y., and formed the nucleus of the present military academy. In 1S3S the corps was increased to 47 officers, and a corps lOgraphical engineers organized and added to it. miners, and pontoniers were added in 1846. At the commencement of the Civil War in 1861 three additional companies were provided for, and also one of topographical rs, which in 1863 was disbanded, and its - posted to the Corps of Engineers. In lSlii; the battalion of engineers was formed be companii already organized, the station .it Willets Point. X. Y. Under act of Congress, approved February 2, 1901, the per nianent engineer establishment was increased to ill' i if four companies each, the com- pany consisting "f 104 enlisted nan. rank and lib-. vii!> i ro additional stall' non-commissioned to each battalion. The band (28 men) is al-o included in the total strength of the corps, which, excluding officers, is 1282 men, rank and file. i gineer School, which vva - for many years at Willets Point, had charge of the instruction of officers of the corps, a- well i arms of the service, in all that pertained •., military lai pneei i ad i oi pedo defense. I pon tic reorganization of tin United state. Army in 1901 the construction ami mainten :e oi i la- torpedo defenses were turned over to the together with the p.. si at Willets Point, I'orl Totten (q.v.), ami the school and on were transferred to Washington, I). C.
lie ., en i rom t lie follow i a tement of
[ineer corp > certainly the most m ii ml ific if not tin- most important branch of the rv service, ami for this reason cadets iii their final examination at West Poinl II3 assigned engineer commis I he dul ies "f this corps comprise reconnoi ing for military purposes, inelud- cp-: selection of sites • I i mates formilil a ry I ion and repair of fori ifica ad their a including t he local ion ict ion of all build urine my fort ideal ion : supplying by i"i A distributii ind elec- tric-lighting supplies for seacoast fortifications; planning and superintending of defensive or offensive works of troops in the field; examina- tion of routes of communication for supplies and for military movements; construction of military roads and bridges. In the held and on active ser- vice they would plan and superintend the con- struction of -field works and fortifications; the removal or creation of obstacles: the planning of military roads and lateral communications for the advance of troops; the more important topo- graphical reconnoissance work, if authoritative survey maps of the theatre of operations cannot otherwise be obtained: the construction and re- pair of bridges; and the general overcoming of such other engineering obstacles as the terrain may disclose or the campaign present. The rank ami file of the United States Engineer Corps are not required to be trained artificers before enlist- ment, necessary instruction being given after- wards. They are combatants, and receive mili- tary as well as technical training. Titles of rank are the same as in the infantry, the enlisted men being divided into privates of the first class ami privates of the second class. See United States, section on Army. European Engineer Corps. The Corps of Royal Engineers of the English Army was first organized in 1763, and has always had its head- quarters and training school at Chatham, near the south coast. Its strength in 1901 was given as 683 officers, 1525 non-commissioned officers and buglers, and 7749 rank and file. The corps is divided into companies, the sappers, as the en- listed men are called, being recruited from men who have served an apprenticeship to some trade, preferably machinists, electricians, car- penters, masons, bricklayers, smiths, painters, printers, telegraphists, etc. The corps has always been on a different basis from the other branches (excepting artillery) of the army, even in the days of the purchase system, which never applied to the engineers. First appointment as a com- missioned officer is obtained through the Royal Military Academy at Woolwich by open com petitive examination. Students are exami 1 and da— el. and receive commissions in the engineers and artillery according to their standing. Thosa -elected for the engineers are sent to Chatham for 1 or more years before receiving their active commission. Officers and men receive extra pay in addition to their regular daily pay. The dis- tinct departments served by the different com- panies are fortress, submarine mines, field, rail- way, and survey: the telegraph battalion consists of three divisions, and the bridging battalion of 10 or more troops. The balloon corps is divided into sections, and the submarine mines into a coasl battalion of 10 companies. The corps is stationed throughout, the British Empire. The pioneer sergeants of all infantry regiments, ar- tificers by trade, must al-o be in possession of a Chatham certificate. Officers ami non-commis- ed officers of cavalry and infantry may also ' btairi certificates a- assistant instructors of field works, if nominated to attend the short course of instruction at Chatham set apart for them. Com- manding officers are required to sec that repre- sentatives of their command are regularly nomi- nated. The French Engineer Corps consists of six regi- ments of sappers and miners, five containing three battalions ami one company of sapper conduc-
