NITROUS ACID. 109 



rods. C. A portion of the rods covered with the melted lead, 

 fo as to form a cylindrical pillar apparently of lead, the iron 

 being perfe6tly coated therewith. 



Fig. 2. D fliews the manner in which the hollow cylinder is 

 formed to any length required, by the junction of a number of 

 ferai-cylinders rivetted together and fitting each other. E, 

 the fide flanges fcrewed clofe together. F, the end flanges 

 alfo fcrewed together, as prepared for the melted lead. 



After a certain portion of the iron rods are coated with lead, 

 the lower parts of the tube are taken ofi'and placed higher up; 

 by which repeated changes, a few tubes will anfwer the pur- 

 pofe to coat any length of the Iron rods. 



XII. 



Reply to Mr. Accum's lajl Letter on the ProduBlon of Nitrous 

 Acid. By W. F. S * 



To Mr. NICHOLSON. 

 SIR, 



X THINK Mr. Accum by no means throws ofl^ the charge Remarks on 

 of cenfure with which he is accufed, upon fo material a part j^^* ^^^^^'^ 

 of the modern theory. He ought to have been more explicit, 

 and in fo nice and fo difputed an experiment, to have given 

 us a minute detail. 



I have performed the experiment which he fpeaks of, but Unfuccefsful at- 

 I could detea no nitrous acid after the procefs. The air gra - '"""P^' '^'''P'f 



•^ _ _ _ o the experiment 



dually diminiflies by the eleftrlc fpark, but this dimjnution is of forming ni- 

 owing to the oxigen gas producing a calcination of the metals '"^^"^ ^^^^' 

 employed, for the pureft oxigen gas anfwers better than when 

 mixed with nitrogen. Therefore I hope, if Mr. Accum pof- 

 fefl!es a more accurate experiment, he will give it through 

 your Journal ; certainly the prefent flate of modern chemifiry 

 requires a very minute inveftigation. I hope, Mr. Nicholfon, 

 you will not refufe inferting this in your Journal. 



London f May 2. 



* See our Vol. X, p. 109 and 214. 



Experiments 



