In cupellation the temperature is high (about 2,000° C.), and fume will escape from the working door and from the opening where the rich lead is fed into the furnace. The danger here is sufficiently recognized by hoods and ducts placed in front of the furnace, but the draught, unless the ducts are connected up with a high-pressure fan, may prove inadequate to carry away all the fume. Flue-cleaning, carried out usually at quarterly or half-yearly periods, is dusty work, as much of the dust is in so fine a state of division as to repel contact with water. Smelting of other metals when the ores contain appreciable amounts of lead is equally productive of plumbism. Thus, in the year 1901 fourteen cases were reported from an iron works for the manufacture of spiegeleisen, the ore (now no longer used) coming from Greece[2]. In previous years it would appear to have been even greater. A remarkable feature of all the reported cases from this factory was that the form assumed was colic, and never paralysis. The poisoning was due to vaporization of the molten lead by the very high temperature to which it was raised as the molten iron flowed out of the furnace on tapping. The danger from fume was limited to the first few feet of the channel, as the heavier molten lead gravitated down between loose brickwork into a pit. Dust collected above the point where the furnace was tapped contained 39·77 per cent. of lead monoxide, and the flue dust 4·22 per cent.[3]. A flannel respirator worn once only by one of the furnace men contained lead equal to 16 milligrammes of lead monoxide. In 1906 three cases were reported in the extraction of copper. The persons affected were employed in charging ore into the cupola[4]. Heavy incidence of poisoning (twelve cases in two months) in a smelting works (now closed) led to examination of sixteen men. The gums of only one man were free of a blue line--in most it was particularly dense--eight were anæmic, one had paralysis of the wrists, and five others weakness. Analysis of the air was made at different points in the factory by the chemist of the works, G. D. Cowan, with the following results: The samples from the cupola were taken from inside the hood (about 5 feet above the men’s heads). The gas was filtered through cotton-wool, so that all solid particles were retained, and the remaining gas was treated separately. The solid particles will be called “dust,” and the gas, after filtration, “fume.” The cupola samples on being examined gave-- Dust, first sample 0·08152 grain of lead per cubic foot. „ second sample 0·07297 „ „ „ Fume, first sample } 0·00526 „ „ „ „ second „ } The samples from the lead well were taken 12 inches above the molten metal at the end of the lead siphon, and gave the following results: Dust 0·05653 grain per cubic foot. Fume Nil.