772 REPORT — 1898. 



me in good stead, and made it possible to put before you the following modest 

 contribution to the subject. 



There is a generally accepted idea that metals have smells, since, if you take up 

 a piece of metal at random, or a coin out of your pocket, a smell can generally be 

 detected. But I hnd that, as commercial aluminium, brass, bronze, copper, German- 

 silver, gold, iron, silver, phosphor-bronze, steel, tin, and zinc are more and more 

 carefully cleaned, they become more and more alike in emitting no smell, and, 

 indeed, when they are very clean it seems impossible with the nose, even if it be a 

 good one, to distinguish any one of these metals from the rest, or even to detect its 

 presence. Brass, iron, and steel are the last to lose their characteristic odour with 

 cleaning, and for some time I was not sure whether the last two could be rendered 

 absolutely odourless, in consequence of the difficulty of placing them close to the 

 uose without breathing on them, which, as explained later on, evolves the 

 characteristic ' copper ' and ' iron ' smell. But experiment shows that, when very 

 considerable care is taken both in the cleaning and the smelling, no odour can be 

 detected even with iron or steel. 



Contrary, then, to what is usually believed, metals appear to have no smell 

 per se. Why, then, do several of them generally possess smells? The answer is 

 simple ; for t find that handling a piece of metal is one of the most efficient ways 

 of causing it to acquire its characteristic smell, so that the mere fact of lifting up 

 a piece of brass or iron to smell it may cause it to apparently acquire a metallic 

 odour, even if it had none before. This experiment may be easily tried thus: — 

 Clean a penny very carefully until all sense of odour is gone ; then hold it in the 

 hand for a few seconds, and it will smell — of copper, as we usually say. Leave it 

 for a short time on a clean piece of paper, and it will be found that the metallic 

 smell has entirely disappeared, or, at any rate, is not as strong as the smell of the 

 paper on which it rests. The smell produced by the contact of the hand with the 

 bronze will be marked if the closed hand containing it be only opened sufficiently 

 for the nose to be inserted, and it can be still further increased by rubbing the 

 coin between the fingers. 



All the metals enumerated above, with the exception of gold and silver, can be 

 made to produce a smell when thus treated, but the smells evolved by the various 

 metals are quite different. Aluminium, tin, and zinc, I find, smell much the same 

 when rubbed with the lingers, the odour, however, being quite different from that 

 produced by brass, bronze, copper, German-silver, and phosphor-bronze, which all 

 give the characteristic ' copper ' smell. Iron and steel give the strong ' iron ' 

 smell, which, again, is quite different from that evolved by the other metals. In 

 making these experiments it is important to wash the bauds carefully after 

 touching each metal to free them from the odour of that metal. It is also neces- 

 sary to wait for a short time on each occasion after drying the hands, since it is 

 not until they become again moist with perspiration that they are operative in 

 bringing out the so-called smell of metals. 



That the hands, when comparatively dry, do not bring out the smell of metals 

 i.s in itself a disproof of the current idea that metals acquire a smell when sliglitly 

 warmed. And this I have further tested by heating up specimens of all the 

 above-mentioned metals to 120° Fahrenheit, in the sun, and finding that they 

 acquire no smell when quite clean and untouched with the hands. 



Again, dealing with the copper group, or with aluminium, wo smell is produced 

 by rubbing any one of them with dry table-salt, strong brine, or with wet salt, 

 provided that a piece of linen is used as the rubber ; but if the finger be substituted 

 for the linen to rub on brine, a smell is observed with copper and German-silver, 

 this smell, however, being rather like that of soda; and, whether dry salt, 

 brine, or wet salt be rubbed on aluminium, a smell is noticed if the finger be used 

 as the rubber, this smell being very marked in the case of the brine or wet salt. 

 Again, although even when linen soaked in brine, or having wet salt on it, is used 

 to rub tin, iron, or steel, a faint smell is noticed, this is much increased when the 

 finger is substituted for the piece of linen. 



As a further illustration of the part played by the skin in causing metallic 

 smells, it may be mentioned that the explanation of certain entirely contradictory 



