To sum up, then, let us say that in putting up electric bells, telephones, etc., there are several points which must be carefully attended to, if satisfactory working is desired; the conducting wires must be as well insulated as possible. Mere touching contacts should be avoided, unless absolutely necessary. If possible contacts or joints should be soldered so as to make a good metallic connection. If any connections are made by terminals or binding screws, they must be carefully cleaned and seen to from time to time; this remark applies especially to the battery terminals, which are more likely to become corroded by the electrolyte. The general arrangement of the wires should be first mapped out on paper, and this plan carefully adhered to in putting them up, otherwise confusion and trouble will arise.