Of its density, body, and covering power, there can be no doubt, and never once have these qualities been called in question. The cost of the manufacture of white lead by the stack process is about 3_l._ to 3_l._ 10_s._ per ton. By the German method, the cost is about the same as by the stack. By Gardner’s electric process, the cost of conversion is 10_s_. a ton. To this 10_s._ must be added the cost of labour expended in preparation, an item which cannot be well estimated on the present limited scale of manufacture; it could not exceed an additional 15_s._ a ton. This would bring the cost of manufacture of electric white lead to 25_s._ a ton. In this electric process inferior lead can be operated upon with success. Brands of that metal such as white lead makers by the stack method dare not employ, may be successfully converted in an electric chamber, and with fair results as to the quantity and quality of the white lead produced. By the use of Gardner’s electric process it would appear that we not only preserve health, but save lives; we not only save time, but interest on large capitals, which lie idle for long periods at a time; and we can economise and simplify the whole manufacture and preparation of white lead, divesting it of all its present cumbersome and unhealthy stages. Gardner’s process, we believe, must take a prominent position as one of the most necessary, valuable, and scientific inventions of modern times. _Hannay’s Process._--Mr. J. B. Hannay, whose name is well known in connection with various chemical and engineering inventions and processes, has recently brought out a process for the manufacture of white lead. The old method of producing white lead or carbonate of lead is one involving much time and labour, together with no small risk to the health of the workpeople. By the new process brought out by Mr. Hannay, sulphate of lead is manufactured direct from galena or lead ore, without the necessity of the intermediate process of the reduction of the ore and the extraction of metallic lead. It is said that the sulphate of lead produced by the new process is whiter and more permanent than the carbonate.