8 4 



NA TURE 



[July 15, 1922 



abrasion in service. It is now usual to remove scale 

 by pickling, by weathering, or by some other suitable 

 method, prior to painting, in order to avoid such 

 disaster. 



A second method of combating corrosion consists 

 in alloying the iron with some other element that will 

 render it incorrodible. This is the principle under- 

 lying the so-called " stainless steel," which contains 

 some 12 to 14 per cent, of chromium, and is remarkably 

 resistant to neutral corrosion, although acids dissolve 

 it with ease. Unfortunately the cost is high, but once 

 that difficulty is surmounted, a vast future lies in store 

 for stainless metals. To realise this it is not essential 

 that the price should fall to that of an ordinary 

 carbon steel. To the writer's own knowledge the 

 cost of painting the steel work in a certain large 

 works recently averaged nearly 5Z. per ton of steel 

 painted. Assuming the paint will not require renewal 

 within five years, the average annual cost is still 1/. 

 per ton of steel. A firm could thus clearly afford to 

 pay considerably extra in initial outlay if by so doing a 

 really incorrodible structure could be obtained which 

 would not require subsequent periodic treatment. 



Yet a third method of reducing wastage by corrosion 

 has been investigated, namely, the removal of the active 

 corroding agent, dissolved oxygen, from waters in 

 contact with the metal. The various means of doing 

 this are discussed by Mr. Frank N. Speller 1 in an interest- 

 ing paper entitled " Control of Corrosion by Deactiva- 

 tion of Water." The method has its limitations, but 

 for hot-water heating systems it would appear to be 

 particularly suitable. The oxygen may be removed 

 either chemically or by purely physical means. A 



1 Journ. Franklin Institute, April 1922. 



satisfactory plant was erected in Pittsburgh in 1915 in 

 which the water is first made to flow through a " de- 

 activator " which is a tank filled with a special type 

 of expanded steel lathing. The steel rusts and thus 

 deoxygenates the water, which then passes on to the 

 heating system and is now non-corrosive. The prin- 

 ciple is simple enough, but in practice it is necessary 

 to pay great attention to the manner in which the 

 deactivator is charged. Miscellaneous steel turnings 

 usually rust together into a tight mass which offers 

 serious resistance to the flow of the water. In a later 

 form of deactivator installed in Boston in 1917 a filter 

 was provided in order to remove all suspended hydroxide 

 of iron. 



Many types of mechanical de-aerators have been 

 designed. The apparatus made by " Balke " in 

 Germany appears to have given satisfactory results. 

 The water at ordinary temperature is sprayed into a 

 chamber carrying a 90 per cent, vacuum, and the 

 released gases are pumped off into a condenser. The 

 efficiency of mechanical de-aerators is of course limited 

 by the solubility of the gases, the temperature, and the 

 power of the vacuum. Normally, therefore, there will 

 always remain a certain amount of unextracted oxygen 

 which may be sufficient to induce gradually serious 

 corrosion in the plant. On the other hand, chemical 

 processes can remove all the dissolved oxygen under 

 favourable conditions. Speller therefore suggests that 

 where very large volumes of water require de-aeration, 

 an economical type of apparatus would be one in which 

 the bulk of the dissolved oxygen is first removed by 

 some simple form of mechanical de-aerator, and the 

 residual oxygen, say the last 5-10 per cent., by 

 chemical treatment. J. N. F. 



Obituary. 



Ernest Solvay. 



ON May 26 last, at the ripe age of eighty-five, there 

 passed away, at his residence in Brussels, in the 

 person of Ernest Solvay, one of the world's greatest 

 industrial chemists. To Nicolas Leblanc belongs the 

 credit of inventing the first successful process for 

 manufacturing artificial soda ; but it remained for 

 the brothers Ernest and Alfred Solvay to provide the 

 world with a pure and cheap product. 



Ernest Solvay was born at Rebecq in Brabant, 

 Belgium, on April 16, 1838. He was the son of 

 Alexandre Solvay, a quarry proprietor and salt refiner. 

 In 1838 two English chemists, Harrison Gray Dyar 

 and John Hemming, patented a process for producing 

 carbonate of soda by acting upon sodium chloride 

 with ammonium bicarbonate and producing sodium 

 bicarbonate and ammonium chloride. The sodium 

 bicarbonate upon calcination yielded soda ash, and 

 the ammonium chloride was decomposed by lime to 

 free the ammonia for re-use. The patentees themselves, 

 and several well-known chemists, erected works to 

 manufacture by this process, but all proved failures, 

 principally on account of the high loss of ammonia. 

 The young Belgian chemist, Ernest Solvay, at the age 

 of twenty-four, was attracted by the process, and, after 

 two years of study and experiment, he devised such 



NO. 2750, VOL. I 10] 



modifications as appeared to him to ensure its practica- 

 bility, and embodied them in a patent in 1863. 



Calling to his aid his brother Alfred, who had been 

 trained for a commercial career at Antwerp and at 

 Hull, they erected works at Couillet, near Brussels, as 

 Solvay et Cie, with a capital of 5440Z. With the 

 starting of these works in 1865 the brothers met with 

 most of the troubles and disasters that had daunted 

 the earlier experimenters. Their experience is perhaps 

 best described in Ernest Solvay's own words : 



I: With the starting of the works in 1865 began the 

 everlasting struggle, the incessant need for improve- 

 ments in apparatus, and the series of accidents in- 

 separable from every new industry. This was the 

 hill of Calvary which we had to climb, and its rough 

 road might perhaps have stopped me if I had not been 

 sustained by my confidence of success in the task that 

 had to be accomplished, and above all by that devoted 

 helper, my brother Alfred." 



In the following year (1866) the works were pro- 

 ducing only \\ tons of soda ash per day, but by 1869 

 the process had proved so successful that the works 

 were doubled in size. During these fateful four years, 

 Solvay had encountered all the difficulties that had 

 baffled his predecessors, both technical and financial ; 

 but, by his application of wonderful scientific skill and 

 his tireless attention to work, he succeeded in evolving 



