Mechanical Theatre--The Boulevards--the derivation of the term. PARIS, ----. "Joy! joy!" cried I, on looking out of the window yesterday, and spying Arnaud returning from the post office with a letter, which, according to our wishes, proved to be from our naughty Jane. Arrant scribbler that I am, I hasten to answer it, though you must feel you do not deserve to be replied to so speedily. However, as this is the first time you have been negligent, we ought not to be relentless--so here is my _hand_ in token of forgiveness and good will; but beware of repeating the offence. Having finished my lecture, and knowing you are fond of listening to adventures, I will now recount a droll one that happened to us last evening. At sunset we were walking on the Boulevard du Temple, which abounds in every variety of the lower order of amusements, when suddenly a violent shower began to fall, and of course every body to scamper to some shelter. _We_ took refuge in the portico of an illuminated building, entitled in large transparent letters over the door, "Theàtre Mecanique," and finally determined to enter and witness the acting within. We accordingly purchased tickets of the woman employed to sell them, and following her up a narrow flight of stairs, were ushered into a confined gallery, overlooking a dirty pit, the highest grade of whose occupants seemed to be that of a cobbler. Four tallow candles lighted the orchestra, where _two hard_ plying fiddlers performed their tasks. We began to think we might be in "Alsatia!" and then the actors and actresses! what were they? Why, a set of clumsy wooden figures that tottered in and out, and were suspended by cords so coarse, as to be visible even amidst the gloom that surrounded them. A ventriloquist made these puppets appear very loquacious; and whenever they stopped to make a speech it was quite ludicrous, for they vacillated to and fro like the pendulum of a clock, for more than a minute. We would have rejoiced to get out, but the rain still poured, and we were compelled to remain. After the piece was concluded, and the fiddlers had put up their instruments, and were puffing out and pocketing the bits of candles, and we were reluctantly preparing to issue forth into the storm, up came the above mentioned vender of billets, (who it seems was manager likewise,) and calling to the musicians to resume their operations, begged us to be re-seated, in order to see the first act repeated, which we had lost by arriving too late. We availed ourselves of her politeness and _honesty_, but could scarcely refrain from laughing as we did so--and fortunately, during the half hour that succeeded, the weather cleared, and we were thus enabled to get home without the dreaded wetting; but the Boulevards not being paved, the walking was exceedingly muddy, and it was so long ere we reached a stand of carriages, that when we did, we thought it more prudent to continue our route on foot, than to risk sitting in our wet shoes.