the Weights of Atoms. 197 



cubic order it seems not possible that the assemblage could 

 have sufficient relative mobility of its parts to give it fluidity) 

 and therefore N would be > 8' 9 . 10 19 . 



§ 49. For carbonic acid, hydrogen, nitrogen, and oxygen, 

 we have experimental determinations of their densities in the 

 solid or liquid state ; and dealing with them as we have dealt 

 with a: 



gases, we 



, irrespectively of their not being monatomic 

 find results for the five gases as shown in the 



following table : 



Col. 1. 



Col. 2. 



Gas. 



CO, 

 H 2 



Arson 



Solid or liquid density. 



Solid 1-58 



liquid at 17° absolute. . . -090 



/liquid 1047 



[solid 1-400 



liquid at its freezing pt. 1*27 



liquid 1212 



solid at 86° absolute ... 1-396* 



Col. 3. 



Col. 4. 



Ratio of 



solid or Xuniber of 



liquid j molecules per 



density to ! cubic centimetre 



standard | of gas at standard 



<jaseous ' density, 



density, 



Col. 5. 



800 

 1000 



833 

 1114 



888 

 681 



784 



Values of q (§48) 



according to 



q-6^=-b9 for argon 



(liquid compared 



■with gas at 0° and 



atmospheric 



pressure). 



45-9 

 3-56 



16-2 

 290 

 150 

 8-9 

 12-8 



3* 

 10 10 



•776 

 1-188 

 •923 

 •837 

 •935 

 1020 

 •960 



In this table, q denotes the ratio to s of the distance from 

 centre to centre of nearest molecules in an ideal cubic 

 assemblage of the same density as the solid or liquid, as 

 indicated in cols. 3 and 2. 



§ 50. According to Avogadro's doctrine, the number of 

 molecules per cubic centimetre is the same for all "perfect" 

 gases at the same temperature and pressure ; and even 

 carbonic acid is nearly enough a " perfect gas " for our 

 present considerations. Hence the actual values of q 6 are 

 inversely proportional to the numbers by which they are 

 multiplied in col. 3 of the preceding table. Now, as said in 

 § 48. all things considered, it seems probable that for argon, 

 liquid at density 1*212, q may be somewhat greater, but not 

 much greater, than unity. If it were exactly unity, N would 

 be 8'9. 10 19 ; and I have chosen ^=('89) _ ^ or 1-020, to 

 make A 7 the round number 10 20 . Col. 6, in the table of § 47 



From information communicated by Prof. W. Ramsay, July 23, 1901. 



