Heavy Chemicals and Alkali

In reviewing the progress made in chemical industries proper, we are met with such a condition of interdependence that it is impossible to avoid overlapping of the subjects to be treated. Moreover, the steps made in the improvement and development of processes, and in the evolution of new products, are so numerous that space will not allow of a comprehensive scheme. Indeed, tbe library of the Patent-office, one of the best for technological literature, cannot contain all that is due to chemists, nor disclose to which chemists the credit should be given for many important advances. We must, perforce, recognise, however, that science is the basis of all substantial development in the industrial arts, and that the ride of thumb is dead. 

This short history of sulphuric acid manufacture should servo to illustrate how tscionco Iras been the primary factor in its ovolution. The subject of the use of iron pyrites as a sourco of sulphur will be deferred until wo consider tho alkali industry.,  

We must digroas for a moment to refer to another industry in order to indicate the origin of the contact process. About thirty-six yoars ago, various methods wore discovered for the preparation of artificial indigo, and endeavours wore made to apply the best of these on a commercial scale to compete with the natural product. Tlio starting material in the most successful processes was naphthalene, at one tinto rogardod by the tar distiller as a nuisance but now rooognisod as a valnablo product. In the 

To return- to the sodium carbonate, we may well ask how many good citizens and washerwomen who use it have any idea that a chemist has anything to do with its production Possibly they think it exists naturally in the condition supplied more probably still, they think nothing at all about it so long as it serves its purpose. 

If the crystals are re-dissolved in water, filtered and re-crystallised, we have the pure sodium carbonate used in pharmacy. By passing carbonic acid gas into a cold solution of the carbonate, and by placing the crystals in an atmosphere of the gas, we obtain the bt-carbonate which is also employed in pharmacy, and as an ingredient of baking powders. 

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In our second chapter we li ve dealt with the heavy chemicals and alkalies, and we will proceed now to consider the production of other chemical substances of value in industry, or useful for domestic, medicinal, scientific, or other purposes. The importance of this branch is so wide and fundamental that it is not too much to say that industry as a whole is largely dependent on an adequate supply of chemical proclucts. The field is so great that we cannot attempt to indicate all or nearly all the substances coming under this head, but we will choose a few examples of different types, all rendered available by scientific methods. 

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