It is delightful to correspond about construction with any trained architect or engineer, because to such a correspondent you can explain everything briefly, with the perfect certainty of being accurately understood. It is terrible toil to have to explain construction by letter to a man who does not understand mechanical drawing; and when you have given great labor to your explanation, it is the merest chance whether he will catch your meaning or not. The evil does not stop at mechanical drawing. Not only do uneducated people misunderstand a mechanical plan or section, but they are quite as liable to misunderstand a perspective drawing, as the great architect and draughtsman Viollet-le-Duc charmingly exemplified by the work of an intelligent child. A little boy had drawn a cat as he had seen it in front with its tail standing up, and this front view was stupidly misunderstood by a mature _bourgeois_, who thought the animal was a biped (as the hind-legs were hidden), and believed the erect tail to be some unknown object sticking out of the nondescript creature's head. If you draw a board in perspective (other than isometrical) a workman is quite likely to think that one end of it is to be narrower than the other. Business correspondence in foreign languages is a very simple matter when it deals only with plain facts, and it does not require any very extensive knowledge of the foreign tongue to write a common order; but if any delicate or complicated matter has to be explained, or if touchy sensitiveness in the foreigner has to be soothed by management and tact, then a thorough knowledge of the shades of expression is required, and this is extremely rare. The statement of bare facts, or the utterance of simple wants, is indeed only a part of business correspondence, for men of business, though they are not supposed to display sentiment in affairs, are in reality just as much human beings as other men, and consequently they have feelings which are to be considered. A correspondent who is able to write a foreign language with delicacy and tact will often attain his object when one with a ruder and more imperfect knowledge of the language would meet with certain failure, though he asked for exactly the same thing.