182 ANNUAL OF SCIENTIFIC DISCOVERY. 



variable proportions in all the waters of the globe. The richness of 

 waters in iodine may be presumed according to the more or less fer- 

 ruginous nature of the lands they wash. Tho proportion of iodine 

 ordinarily increases in water with that of iron, so that waters which 

 are called ferruginous might just as properly be called ioduretted wa- 

 ters. Waters of igneous earths are more ioduretted on the average, 

 and especially more uniformly, than those of sedimentary earths. 

 Though rich in iodine, the waters of the coal formation come after 

 those of certain igneous earths, or ferruginous sediment. The waters 

 of essentially calcareous and magnesian earths contain very little 

 iodine. Iodides are not necessarily proportional to the chlorides. 

 Waters of rivers are, on an average, more ioduretted and less charged 

 with earthy salts than those of springs ; the waters of wells, however, 

 are at once most calco-magnesian and least ioduretted. The proportion 

 which exists between the iron and the iodine of waters, the easy de- 

 composition of the iodide of iron, and the complete decomposition of 

 the iodide of the waters in evaporation without the addition of potassa, 

 render it probable that the iodine exists in them as iodide of iron. 

 Fermented liquors contain iodine ; wine, cider, and perry are more 

 ioduretted than the average of fresh waters. Milk is richer in iodine 

 than wine ; independently of the soil, with which it varies, the propor- 

 tion of iodine in milk is in the inverse ratio of the abundance of that 

 secretion. Eggs (not the shell) contain much iodine. A fowl's 

 egg weighing 50 gr. contains more iodine than a quart of cow's 

 milk. Iodine exists in arable land. It is abundant in sulphur, iron, 

 and manganese ores, and sulphuret of mercury ; but. rare in gypsum, 

 chalk, calcareous and silicious earths. Any attempt to extract iodine 

 economically should be made with the plants of the ferro-ioduretted 

 fresh waters. Most of the bodies regarded by therapeutists as pectoral 

 and anti-scrofulous are rich in iodine. Chatin in the Comptes Pendus, 

 Aug. 



Iodine in Aluminous Schists. Some years ago M. Forchhammer 

 brought forward an ingenious idea respecting the part which the 

 species of Fucus take in the formation of aluminous schists. It con- 

 sisted in admitting that the Fuci, after having accumulated in their 

 substance the sulphates contained in sea-water, converted by putrefac- 

 tion after death the sulphate of potash into sulphuret of potassium ; 

 this in turn precipitated the iron contained in the sea-water in the 

 state of sulphuret of iron, which became mixed with the clay and 

 other substances, some of which are organic, and owe their presence 

 to the putrefaction of the Fuci. Chemical analysis, by demonstrating 

 the presence of iodine in aluminous schists, added a new and powerful 

 argument in favor of this hypothesis. The ash of the Fuci contains, 

 in fact, a considerable quantity of iodine, which might lead to the sup- 

 position that this substance would be also found, at all events in small 

 quantity, in these deposits, if the Fuci really take that part in the for- 

 mation of these schists which M. Forchhammer attributes. Now M. 

 Genteles, while engaged in some researches upon the manufacture of 

 alum, has isolated iodine from the aluminous schists of Latorp, in 

 Sweden. This discovery, joined to that of Duflos, of the presence of 



