tible gases; to effect the perfect mixing of the air and gases; and, lastly, to prevent the resulting mixture from reduction in temperature below that of ignition, before the combustion is complete. These are difficult problems to solve, and the foremost chemical engineers of the day have but begun the attempt at solution. It is satisfactory, however, to know there is a beginning, and we may therefore hope for better things eventually.

In closing this chapter, we cannot refrain from a mention of the able services rendered in connection with the science of chemical climatology as related to the alkali trade, by Dr. Angus Smith, Mr. Fletcher, and Mr. James Mactear. For great difficulties are experienced in determining the rate at which gases issue from chimneys, seeing that the whole volume contained in a shaft does not move at one uniform rate. Beyond the successful removal of these obstacles, these gentlemen have also constructed most accurate anemometers, and have, indeed, laid the foundation of a science in this direction.

Manufacturers would do well to appreciate more fully than they do at present, that science is slow to progress, and on that progress all improvement in industrial applications depends. Let them, therefore, encourage its development by employing competent chemists; and not only so, but rather aid research than war against it, as they have too often done in the past. They cannot hinder the current of knowledge in its advance, but they can help to increase its rate of movement. In another direction they can also benefit humanity, by creating the means whereby their workmen may elevate themselves and train their children, in a better way than is to be witnessed now. Men have other relations one to the

4

other than those included in the commercial world of capital and labour, and this better side of life cannot be hidden even by the shadow of the Stock Exchange and the marts. Indeed, life may be compared to a spectrum with its bright and dark lines.

R

CHAPTER XIX.

STATISTICS OF THE ALKALI TRADE.

THE alkali trade, as it has been described in the foregoing chapters, may be said to be exclusively the growth of this century. The articles manufactured constitute, in many instances, the raw materials for other trades and industries, so that the alkali trade is in some measure dependent on the general state of trade in this and other countries. Consequently, great fluctuations in price and profit are experienced from time to time, a state of things often intensified by too rapid extension of plant beyond. even the demand for the various manufactured products. We have already given many statistics relating to the articles consumed and manufactured in the alkali trade, under the headings of individual substances; here, therefore, we shall only give some figures regarding this industry, as it was fifteen years ago, and, more particularly, as it exists now. It should be remarked that it is a most difficult matter to make an accurate computation of the whole state of the trade, and, indeed, the only approximate one that has been constructed refers to the year 1866. Originally, as we have seen, in the days of the beginning of the trade, comparatively small amounts of products were manufactured, and these were sold at prices which, viewed against those now obtaining, seem ridiculously high. Thus, in 1805, bleaching powder was

worth 1207. per ton; in 1868, its price was 107. 12s. per ton, while to-day it has a value of 41. or 5l. per ton. Again, in 1801, alkali sold at about 497. 58. per ton, and in 1806, soda crystals sold at about 60l. per ton; to-day it is 47. 15s. per ton. In 1736 sulphuric acid cost 28. per lb., or 1287. per ton, while in 1866 it cost 67. per ton; to-day it has a value of 5l. per ton. Bicarbonate of soda now sells at 177. per ton; caustic soda of 60 per cent. at 137. per ton, and chlorate of potassium at 9d. per lb.

Between the years 1852 and 1862, the total alkali trade more than doubled, while in the latter year the annual value of finished products amounted to 2,500,000l. At that date, the raw materials consumed per annum were as follow:-Salt, 254,000 tons; coal, 961,000; limestone and chalk, 280,500; pyrites, 264,000; nitrate of soda, 8,300; manganese, 33,000; timber (for casks), 33,000— total, 1,833,800 tons.

ployed of 2,010,000ʊ.

There was a total capital em

It has been calculated that in 1861 there were about fifty soda works in Great Britain, with about the following

Employing about 10,000 persons, exclusive of mining operations and transportations, etc. Multiplying the above quantities in the first column by 52, to get the annual products, we obtain those in the second column.

Now, according to Messrs. Schunck, Smith, and

Roscoe, the Lancashire district alone, produced in 1861

These quantities were calculated from the returns made by twenty-five works, so that, in comparison with the above figures relating to the whole of Great Britain, a very good idea is obtained of the distribution, so to speak, of the trade at that time.

Advancing to 1866, and acting on very good returns from twenty manufacturers in the Lancashire district, with the estimated production of six, it is found that 194,000 tons of salt were decomposed, with the production of the following quantities