66 PRESIDENTIAL ADDRESS SECTION li. 



It is used in admixture with asbestos for covering boilers and 

 steam pipes, and for preparing brass and metal polish. There was 

 a small production of the mineral in 191 3, but, so far as I am 

 aware, none of the deposits are being worked at present. 



Salt. 



The salt industry of the Union continues to make steady 

 progress, though very little is heard of it, and information 

 regarding recent progress is difficult to obtain. The whole of the 

 output, amounting at the present time to nearly 60,000 tons per 

 annum, is derived from salt-pans, most of which are located on 

 the Dwyka tillite or shales. The supply of salt, which owes its 

 origin to a process of natural concentration, is constantly 

 replenished, and the pans, as pointed out by Rogers and Du Toit,* 

 are undoubtedly among the most valuable assets of the country. 



For the actual production and refining of the salt, solar 

 evaporation in shallow pans is generally relied upon. This system, 

 while very economical, has the disadvantage that the output is 

 dependent on weather conditions, being greatly diminished during 

 the winter months, when very little evaporation takes place. To 

 remedy this, some of the salt companies have of recent years 

 supplemented their evaporating ponds by furnace-heated pans, 

 which enable a fairly steady output to be maintained all the year 

 round. 



Cement, Clay Products, and Siructukal Material. 



The value of the output of the industries under this heading 

 amounted in 1917 to £877,934, an increase of £255,941, compared 

 with 191 3. This is due largely to the great expansion of the local 

 cement industry, which is now supplying the whole of the rapidly- 

 increasing South African requirements. The Union has three 

 large cement factoreis, and the erection of two others is con- 

 templated. 



The clay and pottery industries have also made very satis- 

 factory progress, the cutting-ofT of oversea supplies having given 

 a great impetus to the production of roofing tiles, stoneware, and 

 fireclay goods. There is also a magnificent opening for the local 

 manufacture of electrical insulators, sanitary ware, and crockery, 

 and the ceramic industry appears altogether to be capable of very 

 considerable expansion. 



The great shortages of bottles has led to the establishment of 

 a bottle factory at Dundee, in Natal. The glass is obtained by 

 melting broken bottles. The actual manufacture of glass is, 

 however, also to be undertaken shortly, sand for this purpose 

 being available at several localities. 



It is to be hoped that this and other industries that have 

 come into existence as a result of the existing conditions, will be 



* Cf. The Geology of the Cape Colony, p. 478. 



