Charts of the keyboard are furnished with each set of letters to guide the operator in writing. This machine requires the same general care as other typewriters. =259. Care of Typewriters.= 1) Read the directions for cleaning and oiling the machine. Keep them for future reference. 2) Do not attempt to take the machine apart. Only readjust parts for which such directions are given. 3) Use only the best grade of typewriter oil, and oil only where indicated. The average machine does not require oiling oftener than from ten to fourteen days. 4) Brush the entire machine each day before using. This prevents the accumulation of oil and dust, which retards the free action of the machine, and rusts or clogs the bearings and other parts. 5) Use a stiff brush to clean the type. If the type has become gummed with ink from lack of care, moisten the brush with alcohol or gasoline, and brush it until clean. Avoid cleaning the type with a sharp instrument, if possible, as it mars the edges. However, in case of the letters having an enclosed parts, such as _c_, _d_, _e_, _b_, _g_, _p_, _a_, _s_, _c_, _q_, it may require the careful removal of the deposit with a pin. After this treatment, the type should be well brushed. Keep machine covered when not in use. With proper care, a machine should stay in good order indefinitely. If, in any way, any part of a machine is out of adjustment, have an expert readjust it. =260. The Hectograph.= The hectograph is one of the simplest devices for obtaining duplicate copies of written work (Fig. 147). It is a sheet like heavy paper or pad of jelly-like substance on which a reversed copy of the writing can be made and from which copies can be taken. The original copy is written with hectograph ink on smooth paper by hand, or on a typewriter, and allowed to dry. This copy is placed face downward on the hectograph pad, which has been moistened and rubbed to insure the contact at all places. It is allowed to remain here for three or four minutes. More time is required in cold weather, as the absorption of ink by the pad is slower. The paper is then removed, leaving a reversed impression on the hectograph plate. Copies are then made by placing dry paper on the impression and removing them instantly. Twenty copies may be taken. The plate should be washed in lukewarm water immediately after use. The hectograph plate should be about the temperature of an ordinary room; chilled plates produce faint prints. Never use cold water on the plate. Keep pen flowing freely when writing the original copy, by wiping it frequently. Keep the hectograph covered when not in use. [Illustration: _Fig. 147._ Hectograph.]