There are three sources from which nuisance may arise in lamp-black making: 1. The smoke which issues from the chimney of the black-house, small as it sometimes is, often constitutes a nuisance to near neighbours; but the nuisance is not a very serious one, and it does not extend very far from the works, never to a greater distance than about 50 yards. The odour, even when but little smoke escapes, is oppressive and suffocating in character, and resembles that diffused in a room by a smoking table-lamp. It occasions headache, but is not otherwise injurious to health. 2. A similar nuisance of suffocating smoke sometimes proceeds from the burners, but this is when they are leaky or when there is a deficiency of draught through the black-house, or when the doors of the burning chambers do not shut closely, and when there is much wind blowing past them. This nuisance chiefly occurs when the burners are open to the air and merely protected by an open shed. 3. The escape of acrolein and other offensive vapours from the calcining house. The best mode of preventing nuisance from the black-house is so to elongate the chamber as to give abundant opportunity for the soot to deposit in the course of the smoke along it to the outlet, and by taking means to consume by fire what little smoke escapes deposition. A most effectual arrangement for the accomplishment of these ends is to have a black-house 150 feet long, and so divided by partitions within as to cause the smoke to traverse a distance of altogether 500 feet before it finds an exit; the exit from the chamber communicating with a fire, in which the last of the smoke is consumed, and which serves to assist in regulating the draught through the chamber. The regulation of the draught through the burner and black chamber is of importance in order to avoid the escape of smoke from the burners. If the draught be too great, too much black is lost from the chamber, but if, on the other hand, it be too little, the smoke instead of passing into the chamber will come out into the works and create a nuisance, especially where the burners are erected in the open air, under circumstances in which variation in the force of the wind cannot fail to interfere with due regulation of draught. This part of the manufacture should be conducted within a building of some sort.