May 16, 1902.] 



SCIENCE. 



765 



tegration of soap and certain dirt, and the 

 insolubility of other dirt; sugar and salt at 

 the breakfast table teach solution; the 

 settling of fine mud in the brooklet's pools 

 teaches decantation; the clearness of the 

 spring exemplifies filtration; the tea kettle 

 and soda-water teach ebullition ; the drying 

 roofs show evaporation ; the sweating of 

 the ice pitcher illustrates the principle of 

 the dew point; the sponge teaches surface 

 tension. All these and a hundred like 

 images already exist in the memory, and 

 have but to be recalled to become vivid, but 

 to be interpreted to serve as types of our 

 chemical and physical phenomena. 



But of metallurgical conditions the 

 youth 'spasthas given little foretaste. Espe- 

 cially is this true of the solvent fluxing 

 action of that high temperature at which 

 the rocks and most of the metals are as 

 water, many other metals are gaseous, and 

 strength and even solidity itself are to be 

 found in only a very few substances. And 

 even these react energetically on almost 

 everything they can touch. In the crucible 

 of the iron blast furnace there is but one 

 substance which remains solid, which can 

 offer support, and that is carbon; but this 

 itself reacts on most things exposed to it, 

 and is in turn attacked and destroyed by 

 them. This reciprocal destruction, this 

 Kilkenny-cat attitude of nearly every 

 available substance toward every other, is 

 not only itself unlike anything the student 

 has previously known, but it results in a 

 difficulty previously unthought of, the 

 baffling difficulty of devising any retaining 

 vessel whatsoever. The solids we children 

 have known stay put; the liquids rest 

 peacefully in the familiar tin can, or, in 

 the few cases in which this may not be used, 

 then in vessels of wood, glass, porcelain or 

 clay indiscriminately. 



Indeed, the fiery magmas with which 

 metallurgy has to do, the molten metal, 

 molten slag and molten matter, are in them- 



selves and apart from their corrosive na- 

 ture substances unlike anything in the 

 notice of our early years, which has been 

 directed chiefly to solids and aqueous 

 liquids. The nearest approach to acquaint- 

 ance with this class is the hazy conception 

 of lava streams of which we have read. 

 Still more remote from our experience 

 are the reactions between these plu- 

 tonic bodies which play so large a part 

 in metallurgy, the purifying action of 

 slag on metal, the slag's retentivity of 

 metal or of metalloid, according to whether 

 it is acid or basic; the coalescing of the 

 oxides and acids into one magma, the 

 slag; of the sulphides into a second, the 

 matte; of unoxidized and unsulphuretted 

 elements, both metals and metalloids, into 

 a third magma, the metal; and the recip- 

 rocal expulsion which each magma exerts 

 towards the other. Here indeed we have 

 a class of bodies and of reactions so unlike 

 those of which the usual chemical labo- 

 ratory instruction treats, that metallurgical 

 laboratory practice should be added to 

 chemical. 



To supply clear conceptions of these 

 strange metallurgical conditions, and thus to 

 build a foundation for thought and reason- 

 ing, is I believe the chief work, the invalu- 

 able work of the metallurgical laboratory. 



To build this foundation well, the student 

 should, I think, perform a great variety of 

 simple experiments, each of which should 

 direct his attention to a very few or even 

 to one important principle, and avoid di- 

 verting it to attendant administrative de- 

 tails. For instance, his furnaces should in 

 general be heated by gas or electric resist- 

 ance, so that his attention may be concen- 

 trated on the phenomenon which he is 

 studying, and not diverted to keeping a coal 

 fire in proper condition. As far as possible 

 these experiments should be quantitative. 



If I am right in saying that the labora- 

 tory is thus an invaluable instrument for 



