lxxviii GENERAL SUMMARY OF SCIENTIFIC AND 



the oxidation of the sulphurous oxide by air m presence of 

 ferric oxide' at a high temperature. 



Nichols, under the direction of the State Board of Health 

 of Massachusetts, has examined the composition of the air at 

 different depths below the surface of the " Back Bay lands" 

 in Boston. In three experiments, the depths being three and 

 a half, two, and ten feet respectively, no hydrogen sulphide 

 was detected, ammonia was found in minute quantity, and 

 carbonic -dioxide gas existed in proportions varying from 

 one and a half to twenty-one parts per thousand of air. 

 This amount was approximately proportional to the depth, 

 and reachecL a maximum in August and September. 



The subject of nitrification in soils has been studied by 

 Fittbogen, who has made a series of experiments on the effects 

 of air, with various compounds of potash, lime, magnesia, and 

 of other substances, including quartz sand, on the formation 

 of nitric acid and ammonia in peat. The greatest gain of 

 nitric acid was produced by carbonate of potash ; carbonate 

 of lime, caustic lime, and caustic magnesia were next in order 

 of efficiency ; with gypsum and sand less nitric acid was 

 formed than when the peat was simply exposed to air, with 

 no admixture. The amount of ammonia in the peat increased 

 under the influence of air alone, but decreased in each case 

 when mineral matters were added to the peat. Fittbogen 

 suggests that the marked power of carbonate of potash to 

 aid the formation of nitric acid from the nitrogen of organic 

 compounds in the soil may explain in part the usefulness of 

 wood ashes as a fertilizer. Their potash would not only act 

 directly as plant food, but would also be especially efficient 

 in furthering the change of the combined nitrogen of the soil 

 into forms more fit for the nourishment of vegetation. 



Ditte has proposed a new and simple mode of determining 

 boric acid, which depends upon the crystallization of calcium 

 borate when a salt of boric acid is introduced into a fused 

 mixture of one part calcium chloride and three parts mixed 

 sodium and potassium chlorides. This crystallization takes 

 place upon the surface of the fused chlorides in the form of 

 a ring on the sides of the crucible. Being insoluble in water, 

 the calcium borate is left when the mass is treated with cold 

 water, and may be collected on a filter, dried, and weighed. 



Schnetzler has investigated the action of borax upon 



