Without a personal visit to the Post-office, it is perhaps difficult to gain any correct impression of its immensity, or of the perfect discipline and order which prevade the buildings devoted to postal and telegraphic work. It is a visit which should be made by every one interested, if possible. They would then marvel that we get our letters and papers in the short time we do, if they were to see the thousands upon thousands that are poured into St Martin's-le-Grand day by day. The General Post-office never sleeps save on Sunday between twelve and half-past one. The work is never at a standstill. We began our visit to St Martin's-le-Grand by inspecting what is known as the 'blind' department, where letters with indistinct, incomplete, and wrongly spelt addresses are puzzled out by those specially trained in solving such mysteries. Scrap-books are kept in this department, into which the curious and amusing addresses originally inscribed on the face of letters transmitted through the Post-office are copied and preserved. Whilst we were looking at these a post-card was handed in to one of the officials merely addressed Jackson. Whether the sender thought it would go around to the various Jacksons in London, we know not, but anyway it was decided to take the trouble to return it to the sender, advising him that it was insufficiently addressed. The trouble careless persons give the Post-office is inconceivable, and the way some try to cheat in the manner of registering letters needs to be seen to be believed. From the 'blind' department we were conducted to the 'hospital,' where badly done up letters and parcels which have come to grief are doctored and made sufficiently secure to reach their destination. When it is recollected that postage is so cheap, the outside public might at least take the trouble to do up letters and parcels properly without putting the Post-office to the enormous trouble thus caused--needless trouble sustained without a murmur and without extra charge. Some are put into fresh envelopes, others are sealing-waxed where slits have occurred, and others are properly tied up with string. All this trouble might be saved by a little forethought on the part of the senders. The number of samples that different firms send through the post each day is astonishing. It is said that 1,504,000 pattern and sample packets are posted annually in the metropolis. In addition to those just mentioned, alpaca, corduroy, gloves, ribbons, plush, whalebone, muslin, linen, biscuits, oilcakes, pepper, yeast, toilet soap, sperm candles, mustard, raisins, &c, are sent by sample post. One firm alone posted 125,418 packets containing spice.