96 



M. E. Wiedemann on the Specific /hat* of Gases. 



heat of hydrogen at varying temperatures, inasmuch as Reg- 

 nault lias shown that in the case of this gas the specific heat is 

 independent of the temperature. Neither did an examination 

 of oxygon or of nitrogen appear to be necessary. Kegnault 

 has shown that the specific heat of the first, referred to volume, 

 is the same as that of air ; the same must therefore hold good 

 for nitrogen. Inasmuch also as air exhibits no change of spe- 

 cific heat with change of temperature, we must believe that 

 neither is there any change in the case of its constituents. 



Carbonic Acid. 



The carbonic acid was generated in a Kipp's apparatus from 

 marble and dilute hydrochloric acid. It was purified from 



traces of h 



vuroc 



hloric acid by 



through 



solution of 



sodium bicarbonate, and was then dried by means of sulphuric 

 acid. The carbonic acid employed never contained more than 

 from -J to 1 per cent, of air when examined after coming from 

 the balloon. 



The following Table contains the results of the experiments. 





Table I. — Experiments between 



100° and 20° 



to 25°. 





h 



2. 



3. 



4. 



5. 



6. 



7. 



8. 



9 - ! 



w... 



59-84 



5915 



60-63 



60-63 



60-70 



60-85 



59-82 



59-74 



60-04 | 



G-... 



15-13 



1512 



1751 



1417 



13-72 



16-12 



16-83 



1610 



17-27 



B ... 



755-90 



755-43 



755-60 



755-7 



755-72 



746-9 



746-9 



745-3 



745-36 



p ... 



1770 



16-60 



17 2 



174 



18-3 



20-5 



212 



222 



20-5 



:X ••• 



8610 



66-50 



75-48 



82-82 



56-83 



77-5 



78-74 



61-61 



69-36 ! 



\n ... 



u 



4 



H 



H 



4 



4 



4 



U 



*i 



\a ... 



336 



3-78 



404 



422 



3 43 



403 



416 



3-58 



3-84 | 



r ... 



18-00 



1670 



170 



17 4 



17-8 



20-45 



4-20 



21-9 



22-8 



jT... 



1710 



171 



16-82 



16-3 



17-3 



2052 



18-42 



1751 



21-7 



Vat ... 



0075 



007 



0-079 



0075 



0-073 



043 



0075 



0011 



0067 j 



IT,... 



25 24 



25 06 



25-80 



24-25 



24-46 



27-95 



26-93 



26 



29-62 i 



\m, ... 



-0023 



-003 



-004 



-0-024 



-0-013 



-0-06 



-0 023 



o-oo 



-004 



*..: 



0-0642 



0076 



0-085 



00616 



0-0669 



0-044 



00429 



00563 



0-0521; 



a. ... 



00121 



00127 



0014 



0-0125 



0-0120 



00139 



00115 



0013 



00135 



9 ... 



792 



7-82 



9-0 



772 



6-97 



749 



8-35 



8-10 



7-84 | 



0,... 



7-81 



7-74 



8-89 



7-64 



6-83 



753 



8-35 



7-86 



7-79 ! 



t ... 



21-36 



21 22 



21-40 



20-46 



2100 



2437 



22-82 



21-95 



25-8 



31... 



99-80 



99-80 



99-80 



99-80 



99-80 



98 60 



100-25 



101-25 



97-5 



'e ... 



78-44 



78-58 



78-40 



79-34 



78-80 



74-23 



77-43 



79-3 



71-7 



r- 



0-2084 



0-2081 



0-2101 



0-2095 



02113 



0-2086 



0*2091 



0-2061 



0-2082 



The mean value is 0*2088 ; the greatest deviation from this 

 is 0*0027. Experiments 1-5 were carried out about a month 

 before experiments 6-9. In the first experiments the heating- 

 vessel was filled with boiling water, in the latter with melted 

 paraffin. 



