Whether you know the proper cab-fare or not, always make a bargain with the cabman when hiring his vehicle; and take a note of his number. Keep the right hand side of the pavement when walking. If out with other country friends, keep well together. Observe caution while crossing crowded thoroughfares. In asking for information, apply to shopkeepers, or to policemen, rather than to passers-by. The London police are, for the most part, reliable men; and strangers in any doubt or difficulty can generally obtain useful aid from them. Be on your guard against pickpockets in crowds, street exhibitions, and omnibuses. Beware of strangers who endeavour to force their acquaintance on you, and affect to be unacquainted with London; they are often low sharpers. Keep no more cash about you than is needed for the day’s supply. Be cautious in opening your purse or looking at your watch in the streets. Avoid low neighbourhoods after dark; if there is anything worth seeing there, see it in the daytime. Disregard street-beggars; residents only (and not always even they) can tell the deserving from the undeserving. COMMISSIONAIRES OR MESSENGERS. These are a body of retired soldiers of good character, who were originally organized in 1859, by Captain Walter. Their central office, open day and night, is at Exchange Court, 419_a_ Strand, where men can always be hired. But they are also to be seen, and are easily recognisable by their neat dark green uniform and badge, in most large thoroughfares. Their tariff is,—twopence for half-a-mile or under; and threepence for any distance over half-a-mile to a mile. Back fare, or charge for return, (unless bearing a return message,) is not allowed. A charge of one penny per mile extra, if the parcel carried weighs more than 14 lbs. If engaged by time, sixpence per hour, twopence a quarter of an hour, half-a-crown for a day of eight hours. By special arrangement, they may be hired at from 15s. to 20s. per week. THE GREAT INTERCEPTS MAIN DRAINAGE SYSTEM OF LONDON.