330 



SCIENCE. 



[N. S. Vol. XXIII. No. 583. 



number of experiments were detailed, indi- 

 cating the conditions which promote the 

 corrosion of iron. As nearly as pos.sible, 

 the conditions existing inside a boiler were 

 reproduced, using an autoclave, within 

 which were placed vessels containing sam- 

 ples of iron submerged in various solutions 

 and the whole maintained at 100 pounds 

 steam pressure. 



Briefly stated, the results showed active 

 corrosion to occur in presence of organic 

 material, especially the tannins, also when 

 oxygen or carbon dioxide was generated 

 with the steam, as well as with the well- 

 kaown conditions where salts of calcium or 

 magnesium nitrate or chloride were pres- 

 ent. These results readily explain the 

 cases of corrosion met with in these south- 

 em waters. The other difficulty, that of 

 foaming, occurs in general when the alka- 

 lies of whatever sort are present to the 

 extent of fifty grains and over per gallon. 

 But this difficulty is greatly accentuated 

 by the presence of free sodium carbonate 

 and for the reason, as seems evident from 

 experience, that the finely divided precipi- 

 tate which results, in conjunction with the 

 free alkali, are the chief elements in the 

 promotion of foaming. 



Along the same line is the explanation 

 for foaming when the use of a water con- 

 taining free alkali is followed by the addi- 

 tion of a turbid water, like that of the 

 Mississippi River. 



The very extended use for sanitary rea- 

 sons in the regions farther north, of deep 

 well waters has revealed the fact that this 

 type of water having from thi-ee to fifteen 

 grains per gallon of free sodium carbonate 

 is distributed over very wide areas and 

 brings into prominence their behavior when 

 applied to locomotive use. 



It is thus seen that the problems connected with 

 railway service are altogether different from those 

 that attend the use of stationary boilers. They 

 involve no very profound chemical principles and 



perhaps on that account have received little at- 

 tention, but the industrial importance of the 

 matter is very great and if for no other reason 

 the subject may be worth noting here as an illus- 

 tration of an improved and more healthy state 

 of affairs in the industrial world, which shows 

 itself in giving attention to wastes and greater 

 care in small economies. When we acquire, and 

 there are many indications that we are attempt- 

 ing, the habit of looking after all possible wastes 

 and losses from principle, the profits are more 

 sure to look out for themselves. 



This will appear in full in the Journal 

 of the American Chemical Society. 



W. D. Bancroft delivered an address on 

 ' The van 't Hoff-Raoult Formula. ' 



The apparent osmotic pressure depends 

 on the molecular weight of the solute and 

 on the heat of dilution. If the latter is 

 zero, as at infinite dilution, the apparent 

 and the theoretical osmotic pressures coin- 

 cide. If the addition of one liter of solvent 

 to one liter of a normal solution causes a 

 heat effect of one gram calorie, the appar- 

 ent molecular weight of the solute may be 

 ten per cent, in error at 0°. In all cases 

 in which there is a marked evolution of 

 heat on diluting the solution, the apparent 

 molecular weight will decrease with in- 

 creasing concentration. Instances of this 

 are sodium in mercury, resorcinol in alco- 

 hol, sulphuric acid, caustic potash, or cu- 

 pric chloride in water. The abnormal 

 behavior of sodium chloride in concentrated 

 aqueous solution is due to another cause. 

 The paper wiU be published in the Journal 

 of Physical Chemistry. 



After this the meetings of the sections 

 were resumed. 



BIOLOGICAL CHEMISTET. 



Wm. J. Gies, chairman. 



Investigations on Salts of Casein: J. H. 



Long. 

 The Relation of Carion Dioxide Excretion 



to Body Weight: G. 0. Higley. 



