on of those who are directly engaged yments, or are investing their money or enterprises, no one has a more he proper construction of electrical esentatives of insurance companies. ce agent duly appreciates if he does ate, the hazard that may be caused 1 construction. How to recognize he sees it, and how to avoid it, is, It and often an unsolved problem. of safety is one of ordinary building hazard is easily seen, when once it out, and the remedy is usually as nd understood. When we come to however, we often find that the mind ne, except the so-called electrical ways explain, and even when one concludes that obtained a clear and satisfactory understanding azard and its remedy, he is straightway confronted some astounding statement or some apparently rious phenomena. as occurred to us that possibly the principal reason host persons have such an indefinite knowledge of he simple things in the application of electricity at electricity has almost a language of its own. description of anything electrical by an electriis filled with such terms as "volts," "amperes," is," "rheostats," "induction," "electro-motive etc., etc. Every day adds new words to this ar vocabulary, so that even the electrical engineer be well-read, to keep track of all these electrical A good sized electrical dictionary has already published, but this would have to be revised as as the Chicago city directory to keep up with the ive genius of the men who coin electrical terms. these electrical terms are useful and necessary, seems to us that their great number has discourmany from the study of practical things which wish to know, and which are easily understood if ssed or explained in common, every-day language. ur intention in this and succeeding chapters, to s that part of electrical construction which has a bearing on the question of safety, and it will be Im to do this, as far as is possible, in ordinary age, avoiding technical expressions when we can, hen they cannot be avoided, as must often be the we shall try to give a simple explanation or on of the express.cnN, D s safe and another is n g a task at which son more was to us. undertaking is a laudable equal to our expectation least, help to open a path impossible in this boo of electrical constructi xpressions, not going into a scientific ng to give definitions which shall be ematically precise, but simply giving as will, we hope, enable the unsciena conception of what is going on in cal wires, and to see clearly why one nother is not. ose to assume that the reader knows ut electricity, and we offer our apolany who may feel that their intelliWe also apologize to those who have the same thing in technical language ormulæ, for our audacity of underhich so many of them have been are not prompted by conceit in our all who have long been engaged in have been met daily, for years, with ds from men who had no time to ks, but who wanted a simple explaI electrical. Usually we have been e matter in question in ordinary sfaction of the inquirer, and often go away with the knowledge of the red his purpose perfectly, and was more satisfactory to him than our o us. We feel, therefore, that our dable one, and if our success is not tation, we hope that we shall, at a path for others. It is, of course, book, to cover the entire field uction or even the applications of DEFINITIONS OF CO f an engine or water re can direct and regulate ductors, and transform icity that might interest our readers. We have, fore, decided to take up the subject purely from isurance man's point of view. We shall consider electricity as it may or may not create a hazard. is subject has been carefully and very completely ed in the rules known as the "National Code." code in its original form, or as revised and incored into the regulations of the various insurance iations, is familiar to every one in insurance lines. however, condensed in form, and full of technical ;. We have, therefore, thought it proper to take code as our text. We shall endeavor to explain ode in every-day language, giving such definitions explanations as will, we hope, enable any one to rstand its meaning without the assistance of an rical dictionary or electrical text books. We shall up the various points in the same order that they aken up in the code. The National Code is the ome of experience. It is the result of a great int of study and discussion. It stands to-day as est expression of what is definitely believed by the t men of both insurance and electrical lines, and e shall succeed in assisting any one to a better rstanding and appreciation of its principles, we feel repaid for our efforts. The following definiare absolutely necessary to describe the most non terms which constantly appear in the code. ectricity.—We do not know what electricity is, and useless for us to try to define it. We perceive it as nifestation of energy. All we need to know of its e for our present use, is that we can transform the firm of "fight, heat, or w s but one kind of eletr manifests itself to us. mitation of light, heat and electricity, or ele** Extra Current-While we n motion, still, as its is but imperfectly at s, however, to have some tons. For all ordinary F tricity to be a fluid, and e water in a pipe. Follow ime during which it flows. city is called "the curren or water-wheel into electricity, and and regulate its distribution by wires d transform it again into energy in heat, or work, in moving a machine. ind of electricity, as far as we know, tself to us in various ways. In the t, heat and power, we deal only with ity, or electricity in motion. -While we have to deal with elecstill, as its nature is not known, its erfectly understood. It is necessary o have some theory to account for its ordinary purposes, we may consider fluid, and to have a motion in a wire e. Following this analogy, we speak electricity. As with water in a pipe h electricity, the amount of flow is e strength of the current, and to the it flows. The rate of flow of electhe current strength," or, more coment." It is measured by an arbitrary "ampere." The ampere is the unit h. The total amount of electricity urse, be measured in "ampere hours." ordinary 2,000 c. p. arc lamp, such as in street illumination, requires a curs. If the lamp burns for 10 hours, I of current consumed will be 100 When we speak of a wire carrying a eres, we mean that 10 units of current e wire, and we use the expression in |