458 



PROFESSOR W. DITTMAR ON THE BEHAVIOUR OF THE 



slightly attacked by the alkali. In the subsequent experiments, the nitrogen was 

 prepared by shaking air with a solution of pyrogallate of soda in one of the bottles of a 

 Pisani gas-holder, the indiarubber tube connecting it with the other being clipped 

 meanwhile. Our Pisani enabled us to operate on about 10 litres of air at a time; and 

 24 grm. of caustic potash sticks, 10 grm. of pyrogallol, and 400 c.c. of water were 

 found to be convenient quantities for that volume of air. In each experiment we had 

 two Pisanis full of nitrogen ready, and both so connected with the apparatus that, as 

 soon as one was emptied, the other could be substituted for it without loss of time. The 

 nitrogen of the gas-holder was, however, not used as it came out, but first passed through 

 a tower of sulphuric acid and pumice, and thence through a tube full of red-hot copper 

 gauze, before it entered the porcelain tube. The results of Experiments 7, 8 and 9 are 

 given in the following table : — 



Time of heating* 

 Product obtained, 

 C0 2 from it, . 

 Na 2 S0 4 from it, . 



From these numbers we have in percentages : 



Carbonic acid, . 



Soda, Na 2 0, 



Water, by difference, . 



100-000 



(7) 



(8) 



(9) 



1-5 



2-5 



6 - 5 hours 



1-9978 



1-731 



2-0804 grm. 



0-8009 



0-689 



0-8385 



2-7096 



2-358 



2-8220 1 



mtages :■ — 







(7) 



(8) 



(9) 



40-089 



39-803 



40-304 



59-252 



59-509 



59-258 



0-659 



0-688 



0-438 



100-000 



100-000 



Or, by calculating the C0 2 into Na 2 C0 3 , and the water into NaOH, 





(7) 



(8) 



(9) 



Carbonate of soda, 



. 96-681 



95-991 



97-199 



Hydrate of soda, NaOH, 



2-933 



3-062 



1-949 



Oxide of sodium, Na 2 0, 



0-388 



0-948 



0-852 



100-002 



100-001 



100-000 



In Experiment (10) the weight of dry carbonate started with was 2*3407 grm.; the 

 heating, after attainment of the highest temperature, was continued for two hours ; the 

 loss of weight which the substance suffered was 0*1004 grm. Two analyses of the product 



were made ; the results were as follows : — 



I. II. 



Substance taken, 1*2564 0*941 



Carbonic acid obtained, 0-5107 0-3836 



Sulphate of soda obtained, .... 1-7027 1*276 



* Only the blowpipe used in all cases. 



t Mean of two closely-agreeing determinations. In this Experiment (9) for the first time carbonate of soda from 

 oxalate was used. 



