( 120 ) 



Finally I wish to state that capillary glass tubes of 1 ram.' cross- 

 section, after air, carrying muscon, had been passed through them 

 for live minutes, <!i<l not show a perceptible change of surface tension 

 with water (the tension being measured by the heigh) of the water 

 column) and that repetition of the other experiments with tubes, 

 heated beforehand and with air that had been dried by means of 

 calcium chloride and cotton wool, gave no deviating results. 



At present it is impossible to give a theory of these phenomena. 

 As a preliminary working hypothesis one might suppose the adsorbed 

 muscon to be dissolved in the layer of condensed water vapour and 

 aii- which covers all objects and it might be further assumed that 

 the change ol' muscon into muse only then takes place at a percep- 

 tible rate when the surface action of the metal, of the glass or of 

 the glazed porcelain produces a particularly great density of the 

 dissolved muscon in immediate contact with the surface in question. 

 This hypothesis is in harmony with equilibrium experiments, made 

 with dried air at 0°, '10°, etc.. These experiments are in progress 

 but not completed yet. 



Physiology. — "On the adsorption 'of tin.' smell of muscon />;/ 

 surfaces of different material". By Prof. 11. Zwaardemaker. 

 Continuation of a former communication. 



When air, charged with muscon, is passed through tubes of an 

 alloy of lead and tin, in the manner described in the communication 

 of May 24, the inner surface of these tubes appears to adsorb 

 muscon in quantities, the amount of which may to some extent be 

 estimated from the time, during which the tubes preserve the odour 

 of muscon. This assumption is based on the supposition (hat the 

 adsorption lakes place in one and the same dissolving substance, 

 namely the condensed layer which is said to cover all objects. 



The dilution at which the muscon is present in the air in these 

 experiments, can lie kept constant when the current velocity is 

 controlled by means of an aerodromometer. Moreover, it may vary 

 between certain limits, since experiments, made to this purpose, 

 showed that it makes no difference in the results whether the muscon, 

 volatilised per second from the smelling source, is contained in 

 4_>, 84 or L26 rv. of air. Tubes of lead, alloyed with tin. lose under 

 similar conditions the adsorption odour in the same degree and in 

 the same time, say 5 to l> days. 



