Mr. 11. Pliillips's Letter to Dr. D. Boswell Reid. 4-23 



of the Continuation, viz. whether nitrate of ammonia sublimes 

 at a lower temperature than that at which it decomposes? 

 I will not again take the trouble of restating the conflicting 

 opinions which you have expressed on this subject; but I as- 

 sert that the last is the wrong one, viz. " that nitrate of am- 

 monia can be volatilized at the temperature below that at 

 which it is decomposed." In my Letter I quoted Berzelius to 

 prove that this is not the case ; and you have adopted a new 

 and most ingenious expedient of discrediting his testimony, 

 viz. that his opinion was merely " incidentally" introduced; 

 and you conclude that it is not to be credited because it is 

 expressed when treating of nitrous oxide. Why, Sir, your 

 own opinion, which is as follows, I copy from p. 41 of the 

 Elements; and it occurs "incidentally" when treating of nitrous 

 oxide : " As the nitrate can be volatilized at a lower tempera- 

 ture than it is decomposed, we must expect that a portion will 

 escape decomposition during the preparation of nitrous oxide." 

 Now, if the opinion of Berzelius is of no value because it is 

 incidental, and expressed when treating of nitrous oxide, allow 

 me to inquire of what value is your own, since it is given 

 precisely on the same occasion .'' • • r t> 



I will, however, now present you with the opinion of Ber- 

 zelius, expressed twice over. 1 care not which you deem the 

 "incidental" one, for they possess the advantage of agree- 

 ing, which is not always the case when your "incidental" 

 are compared with your dehberate statements. Berzelius says 

 {Traite de Chimie, tome ii. p. 46), "Le sel [nitrate d'ammo- 

 niaque] est introduit dans une cornue garnie d'une tube pro- 

 pre a conduire les gaz, et qu'on chauft'e a la flamme d'une 

 lampe ou sur quelques charbons. II commence par se fondre, 

 puis il entre en ebullition, et le gaz se degage en grande quan- 

 tite. S'il parait des vapeurs blanches dans la cornue, la cha- 

 leur est trop forte et une partie du sel se sublime." This you 

 term the "incidental" opinion. Now turn to tome iv. p. 13, 

 and tiien you will find the following direct statements respect- 

 ing nitrate of ammonia. "Chaufle rapidement dans une cor- 

 nue de verre, jusqu'a 200% il fond, entre en ebullition, et perd 

 son eau de cristallization ; a 250% il est decompose ayec de- 

 gagement d'eau et de gaz oxide nitreux, comme je I'ai deja 

 dit pafre 46 du deuxieuie volume. Quand le sel est pur, et 

 qu'on °chauffe avec precaution, ils ne se forme aucun autre 

 produit. Mais si la decomposition s'opcre avec une rapidite 

 telle, (|ue le vase se remplie tie fumee on trouve aussi de ni- 

 tiile anuuoniciue parmi les produits de la distillation, de I'am- 

 luoniaciuc et du gas oxide nilriquc." Now, Sir, had Berzelius 



committed 



