metre- i if ;ur do in>t contain les- than 1 ami m>t more than "> milli- 

 gram- i it' ammonia. It is remarkable that mountain air contains more 

 ammonia than the air of \allevs. The air in t host 1 place- where animal 

 -ubstance- underu'erin^ change are accumulated, and e.-pecially that of 

 -'able.-. _'". iei allv contain- a much LiTeater quantity of t hi- Ljas. This is 

 e t-on of the peculiar pungent smell noticed in such place-. .More- 

 nmoiiia, a- we -hall learn in t he following chapter, combines with 

 acids. ;md should therefore be found in air as such combinations, as 

 air contains carbonic and nitric acids. 



Tin- pre-ence of nitric acid in air is proved without doubt by tin- 

 fact ilia; rain-water contains a >omewhat considerable amount of 

 nitric acid, as we shall learn when speaking of this acid. 



Furl her (as has been mentioned in Chapter I V.), air contains <>;<<('. 

 and h\ dr< >_;eii peri ixide/ ' 



I!. --ides substances in a gaseous or vaporous state, ils there is alwavs 

 found a more or less considerable quantity of substances which are not 

 k m>\\ M iii a st ate of vapour. 'I hese substances are c-arried in the air as 

 <///x/. If ,-i linen surface, moistened with an acid, be placed in perfectly 

 pun- air. tlp-n the washings are found to contain sodium, calcium, iron, 

 and potas-ium.- 1 - 1 Linen moistened with an alkali absorbs carbonic, 

 -ulphuric. phosphoric, and hydrochloric acids. l-'urther. the presence 



m,.,| i tl .-iiir. M/,,III- iiinl liy.li'.-rn p.-rnxiili' :it ill. i I rapidlv dis- 



s-Mii-i.li-r.-ilily. iinil.asw. li-.l.i./ ..... -isiiii-t 



! ] r. -i lit ill the ,iir HIM] its |nirit\. tiuit i~. tin- ;iinoiint of 

 in must he -mall. lire. iii-i , i <-i mtact \\ itli 



i I In nr Iiy f\ i.l\ in-_' it li\ ;irtilicial iiicaii- in t In at nm-pluTi- : IW 



; ,,,,.: ,.;,] pai ks tlii-.m-h the si'iil il.it in - |ti|..-- 1. .nlin- air 



: ..lit tlii' ciini- 



i ' tin il thn , inu' i' . l''"i' 



i./niii- 1 h.iu i-iiiuil r\ air. 'I'l I'uriu I In 1 ilis- 

 I ! ,( i'r. animal life I'aiinut r\i-t n a ir i-ont aiiiin^ r a 



.1 i . ,m.| ali ..In. I. ( II. M. ,-. .... |, \Iiinl, h.uiiil to 



