. The Americana : a universal reference library, comprising the arts and sciences, literature, history, biography, geography, commerce, etc. of the world. -mands so many special appliances for their re-quirements that no one description is possible,and an extended catalogue is inadmissible with-in the limits of this article. The earliest knownengineering instrument was the Diopter of Heroof Alexandria, 130 , although rude appliancesmust have been used long before that time by the ancient engineers in the construction of thepublic works of Chakkea and Egypt, the ruins ofwhich even now awake
. The Americana : a universal reference library, comprising the arts and sciences, literature, history, biography, geography, commerce, etc. of the world. -mands so many special appliances for their re-quirements that no one description is possible,and an extended catalogue is inadmissible with-in the limits of this article. The earliest knownengineering instrument was the Diopter of Heroof Alexandria, 130 , although rude appliancesmust have been used long before that time by the ancient engineers in the construction of thepublic works of Chakkea and Egypt, the ruins ofwhich even now awaken our admiration andwonder. It was not, however, until the begin-ning of the 19th century that the great impulseto the construction and use of engineers in-struments was given by the advance of civiliza-tion and commerce incident to the applicationof steam as a motive power on sea and that time great advances have been madenot only in the design and accuracy of engi-neering instruments but also in the inventionof new instruments for the many purposes re-quired by engineers in the construction of rail-roads, canals, bridges, harbors, The characteristics of engineers instrumentsdiffer in the various nations as the requirementsof engineering practice, and thus American en-gineers instruments possess a distinct charac-ter of their own as compared with other na-tions, having as a rule few parts and lightnessof construction combined with great strengthand an adaptability of parts for the specialservice required. It is not the purpose of thisarticle to attempt a description of the variousinstruments used by engineers — this may befound in the article Surveying,— but to givethe reader a general idea of their metals used in the construction of engi-neers instruments are principally the alloys ofcopper and tin with small quantities of silver,aluminum, and German silver. Great care mustbe constantly exercised that these substances be INSULATOR —INSU
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Keywords: ., bookcentury1900, bookdecade1900, bookidamericanauni, bookyear1903
