124 Mr. Gray's Reply to the Editor. [Feb. 



bination, you object to my mentioning the speculations of that 

 chemist on the existence of oxygen in ammonia, in an element- 

 ary treatise. This is mere matter of opinion. Mr. Brande indeed 

 does not make any mention of the supposed compound nature 

 of nitrogen ; but both Mr. Henry (8th edit. vol. i. p. 243) and 

 Dr. Thomas Thomson (6th edit. vol. i. p. 214) not only notice 

 the suspicion of azotic gas, and ammoniacal gas containing oxy- 

 gen, but the one notices the ammonium of Sir H. Davy, and the 

 other the nitricum of Berzelius. So that I have just cause to be 

 astonished at your saying, " If the student after reading this 

 passage were to look into the chemical works of Thomson, 

 Henry, or Brande, he would find no mention either of oxygen 



or nitricum existing in ammonia. 



My idea of the composition of the liquor plumbi acetatis 

 agrees with the statements of Dr. Thomas Thomson, Mr. Henry, 

 Mr. Brande, and Mr. Anthony Todd Thomson. I am again 

 astonished at your saying, that " in p. 81 no rules are given for 

 describing those salts that contain an excess of base." I know 

 not how to account for this, unless by supposing a whole para- 

 graph has dropped out of your copy at press, as single letters 

 sometimes do ; for the third paragraph in that page, consisting 

 of no less than 14 lines, expressly relates to the mode of naming 

 (not indeed describing, as you have by another slip worded it) 

 salts when an acid combines in different proportions with the 

 same base, and five modes of nomenclature are related ; and 

 in the last paragraph of p. 94, the subject is resumed. 



You then proceed to say (for I must now quote your words at 

 length), " On the same ground we object to the following state- 

 ment : Moist iodine added to phosphorus yields a sour colour- 

 less gas, which is rapidly absorbed by water, and must be 

 collected in a quicksilver apparatus ; a gallon of this gas weighs 

 about 311 grains. Here the changes are either I s + P into I 8 

 + P 1 ; or I + P + H 1 into I H + P 1 , and the new acid is 

 called the iodic or hydroiodic." " The pupil would naturally 

 suppose that Mr. Gray considers the iodic or hydroiodic acids 

 (properly hydriodic) as similar ; but he ought to have known 

 that iodic acid consists of oxygen and iodine, and the hydriodic 

 acid of hydrogen and iodine ; it is the latter only which is 

 formed, excepting a quantity of phosphorous acid, of which no 

 notice is taken, nor is the decomposition of the water even hinted 

 at, although the formation of the hydriodic acid depends upon 

 it. (P. 166.)" 



These are your precise words. I pass over any inquiry as to 

 the ground upon which you object to what I have said ; although 

 I am not able to discover any connexion between this passage 

 and that immediately preceding it, respecting the subsalts ; but 

 proceed to your assertion, that I have taken no notice of the 

 phosphorous acid which is formed. This shows how easily slips 

 of the pen may be made, and may abate your astonishment at a 



