Thus, in the home trade in England: if in Kent a man tells me he is to go among the night-riders, his meaning is, he is to go a-carrying wool to the sea-shore--the people that usually run the wool off in boats, are called owlers--those that steal customs, smugglers, and the like.

In a word, there is a kind of slang in trade, which a tradesman ought to know, as the beggars and strollers know the gipsy cant, which none can speak but themselves; and this in letters of business is allowable, and, indeed, they cannot understand one another without it.
A brickmaker being hired by a brewer to make some bricks for him at his country-house, wrote to the brewer that he could not go forward unless he had two or three loads _of spanish_, and that otherwise his bricks would cost him six or seven chaldrons of coals extraordinary, and the bricks would not be so good and hard neither by a great deal, when they were burnt.
The brewer sends him an answer, that he should go on as well as he could for three or four days, and then the _spanish_ should be sent him: accordingly, the following week, the brewer sends him down two carts loaded with about twelve hogsheads or casks of molasses, which frighted the brickmaker almost out of his senses.

The case was this:-The brewers formerly mixed molasses with their ale to sweeten it, and abate the quantity of malt, molasses, being, at that time, much cheaper in proportion, and this they called _spanish_, not being willing that people should know it.

Again, the brickmakers all about London, do mix sea-coal ashes, or laystal-stuff, as we call it, with the clay of which they make bricks, and by that shift save eight chaldrons of coals out of eleven, in proportion to what other people use to burn them with, and these ashes they call _spanish_.
Thus the received terms of art, in every particular business, are to be observed, of which I shall speak to you in its turn: I name them here to intimate, that when I am speaking of plain writing in matters of business, it must be understood with an allowance for all these things--and a tradesman must be not only allowed to use them in his style, but cannot write properly without them--it is a particular excellence in a tradesman to be able to know all the terms of art in every separate business, so as to be able to speak or write to any particular handicraft or manufacturer in his own dialect, and it is as necessary as it is for a seaman to understand the names of all the several things belonging to a ship.

This, therefore, is not to be understood when I say, that a tradesman should write plain and explicit, for these things belong to, and are part of, the language of trade.
But even these terms of art, or customary expressions, are not to be used with affectation, and with a needless repetition, where they are not called for.
Nor should a tradesman write those out-of-the-way words, though it is in the way of the business he writes about, to any other person, who he knows, or has reason to believe, does not understand them--I say, he ought not to write in those terms to such, because it shows a kind of ostentation, and a triumph over the ignorance of the person they are written to, unless at the very same time you add an explanation of the terms, so as to make them assuredly intelligible at the place, and to the person to whom they are sent.
A tradesman, in such cases, like a parson, should suit his language to his auditory; and it would be as ridiculous for a tradesman to write a letter filled with the peculiarities of this or that particular trade, which trade he knows the person he writes to is ignorant of, and the terms whereof he is unacquainted with, as it would be for a minister to quote the Chrysostome and St Austin, and repeat at large all their sayings in the Greek and the Latin, in a country church, among a parcel of ploughmen and farmers.