CHEMICAL SCIENCE. 213 



Dr. McAclam, in a communication to the British Association, 18-18, stated 

 that in striking medals from aluminum, he had noticed a peculiar gray ap- 

 pearance on their surface, which it was supposed arose from, the unclcanness 

 of the die. Close examination, however, showed that this was not the case. 

 Some of these medals were subjected to the action of hydrochloric acid and 

 nitric acid separately, without producing much effect on their surfaces. 

 AY hen some of them were put in a solution of caustic potash they were acted 

 on very violently, hydrogen being evolved, and the surface of the metal be- 

 coming beautifully frosted. This phenomenon of an alkali comporting itself 

 to a metal as acids do, was worthy the attention of chemists. After alumi- 

 num has been frosted in this manner, it does not become tarnished on expo- 

 sure to the action of the air. 



ON THE MANUFACTURE OF STEEL. 



The following paper, read before the Society of Arts, London, by Mr. C. 

 Binks, on the manufacture of steel, is one of the most practical and valuable 

 contributions to science made during the past year. Although of great 

 length, its importance seems to warrant a publication in the pages of the 

 present volume : 



The existing and generally received theory of the formation and the 

 alleged actual composition of steel have ever appeared to have in them 

 points that are not quite satisfactory. But it is probably owing to the fact 

 that chemistry, throughout the whole range, is so replete with instances in 

 which extraordinary effects or phenomena follow from insignificant causes, 

 or from causes apparently inadequate to produce them, that this instance of 

 the alleged composition of steel has been allowed hitherto to pass unques- 

 tioned generally. 



The magical effects (as seen in its assumption of properties so singular 

 and distinctive) of the addition to pure iron of some apparently insignificant 

 proportion of carbon, is a conspicuous instance of this kind of chemical 

 anomaly. That simple combination is, and has ever been alleged to be, the 

 sole cause of the conversion of iron into steel. Carbon has been the only 

 tangible or apparent element brought in contact with the iron in the act of 

 its conversion ; and after analysis of steel has detected in it, or assigned to it 

 as essential, the existence of iron and carbon only. Therefore has this expla- 

 nation ever been generally accepted without misgivings; and, solely to this 

 simple combination, has ever been, and still is, attributed the conversion 

 and consequent assumption by the iron, when it becomes steel, of properties 

 so distinctive and peculiar. Still the broad distinctions that exist in their 

 mechanical or physical properties between steel on the one hand and mallea- 

 ble iron, or cast-iron, on the other, would seem to leave room for great doubt 

 that the cause of these distinctions is due solely to the absence in the one, 

 and to presence in the other, of the element carbon, or to the merely 

 minute differences in the relative proportions of that element that are found 

 in steel and in cast-iron. Yet everywhere is this the received formula of the 

 composition of steel : namely, that it consists solely of about ninety-nine 

 parts of pure iron combined with one part of carbon ; and any other mat- 

 ters that, in extremely minute proportions, analysis may have, from time to 

 time, or occasionally, detected in it, have been considered as foreign and 

 accidental only, and as being in no way essential to, but rather as interfering 

 with, its true chemical composition and character. In this light, for exam- 



