33° 



Transactions of the Canadian Institute. 



[Vol. VII. 



and with many of these substances with which these salts come into 

 contact, form chemical compounds of a more or less stable nature. 

 With this object in view, from the standpoint of vegetable physiology, 

 it was thought advisable here to ascertain in an indirect way whether 

 it be possible for substances in aqueous solutions to leave the solution, 

 not with the liquid as a liquid, or as a vapour in the state in which the 

 particles are so large as to refract and reflect light and therefore render 

 it visible; but to leave the solution with the solvent water, or in small 

 particles that are in the layer immediately upon the surface of the 

 water, at the same moment the water particles become taken up 

 by the air. 



A series of experiments was arranged, as shown in Fig. 1 5. 



Four kinds of iron were obtained: — (i) Chemically pure iron (98.8%); 

 (2) Fine soft iron wire ; (3) Coarse, common iron wire ; (4) Piano 



wire. Each of these specimens of 

 wire was cut up into three approxi- 

 mately equal portions, and one 

 from each specimen was placed 

 under a bell-jar in a watch glass 

 perfectly clean. Under the jar 

 was a crystallizing dish filled with 

 sea-water in one case, salt water in 

 the second case, and pure water 

 in the third. Each jar then had 

 under it four different kinds of 

 iron, and excepting for the liquid 

 used, all conditions were as nearly 

 ] as possible the same. The speci- 

 mens of iron were all weighed with 

 the nicest accuracy upon com- 

 mencing the experiment, and they 

 were in clean watch glasses in order to be able to see if any of the 

 solution happened to be precipitated in any way, or come in contact 

 with the metal while the solution was in the air in the form of a liquid 

 or spray. A liquid containing even the faintest trace of a salt in 

 solution will leave plain evidence of the salt if the smallest part of a 

 drop be allowed to evaporate from the surface of a well-cleaned glass. 

 The surface of the watch glass was very large in comparison with the 

 specimen upon it, and it is fair to conclude that if no salt settled in 

 any way upon the glass none came in contact with the iron in the 

 same way. The jars were each placed upon four glass plates laid 



A 



■<8p- 



^ 



FIG. .5. 

 R, samples of iron ; W, liquid used. 



