11)17.] The Fourth Indian Science Comjress. clxxvii 



On the determination of ozone, oxides of nitrogen and hydro- 

 gen peroxide in atmospheric air. — By B. Sanjiya Had. 



A summary of previous work is given, and the methods employed 

 are criticised. A method has been devised, in which three samples of 

 air, each of 5—10 litres, are shaken for several hours with an extremely 

 dilute standard solution of sodium nitrite, rendered slightly alkaline 

 The first sample, prior to treatment with the nitrite solution, is passed 

 through a tube of chromic acid crystals, whereby hydrogen peroxide is 

 removed ; the second sample is passed through powdered manganese 

 dioxide, which destroys both ozone and hydrogen peroxide but is without 

 action on oxides of nitrogen ; the third sample is collected directly. It 

 is shewn that ozone, even in excessive dilutions, oxidises sodium nitrite 

 in solution rapidly and quantitatively in accordance with the equation. 

 NaN0.2 + 03=NaN0 3 + C>2. Hydrogen peroxide oxidises the nitrite 

 similarly, but only in acid solution. By estimating the amount of nitrite 

 remaining after shaking with the three samples of air, the amount ot 

 ozone, hydrogen peroxide, and oxides of nitrogen can be calculated 

 The estimation of nitrite was carried out colorimetrically by the method 

 of Griess, and using naphthylamine and sulphanilic acid. 



The results of some experiments on the air at Bangalore are recorded. 



1 



Waters 



Their signifi- 



cance to the Municipal Engineer and to the Manufacturer. 

 — By J. H. Barnes and Arjan Singh. 



A brief history is first given of chalybeate waters and the difficulties 

 which have been experienced in making use of such waters for municipal 



purposes and in manufactories. m . 



The problem of iron-depositing waters has arisen in the Funjab 

 where deep waters are being tapped by tube wells and a detailed study ot 

 such waters from different parts of the Punjab is described. The pre- 

 sence of iron bacteria well known in Europe but hitherto unrecorded m 

 India— such as Leptotkrix ochracea, Gallionella ferrugmea (Ehrenberg), 

 Spirophyllum ferrugineum (Ellis) and Crenothrix Polyspora (Conn) is demon 



strated. . ., 



The sub-soil waters of the Punjab show a marked increase in th 

 amount of ferrous iron they contain as the distance from the Himalaya 

 —the source of the water— increases, thus proving a steady now west- 

 wards of sub-soil water. , , . , % , 

 The contact of these ferruginous waters with an aerating agent such 

 as sea water offers a feasible explanation for the formation of the mineral 



limestone. . , „ , A rt i 



The paper includes a description of the methods of analysis used and 

 full tables of the composition of tube well water before and after the mon- 

 soon. In conclusion, recommendations are made for the purification ot 

 these ferruginous waters when making use of these for municipal or manu- 

 facturing purposes. 



Some biochemical factors In the reclamation of alkali soils. 



By J. H. Barnes and Barkat Am. 



The paper first reviews in brief the sources and nature of the salm 

 matter which causes sterility in alkali soils. The view is advanced tha 

 sterility in such soils is not due to any specific toxic effect of the chemicals 



This paper will be published in extenso in the Congress number ot 



l _ 



the Agricultural Journal of Tndia. 



