recent  attack  upon  the  Atomic  Theory,  431 
Comb.  no.     Specific  heat. 
a. 
b. 
aXb. 
Carbon     . 
.     12 
0-147 
1-76 
Oxygen     . 
.     16 
0-155 
2-48 
Boron 
.     11 
0-25 
2-75 
Chlorine  .  ' 
.     35-5 
0093 
3-3 
Sulphur  . 
.     32 
0163 
5-22 
Phosphorus 
.     31 
0-174 
5-39 
Arsenic     . 
.     75 
0-0814 
6-11 
Antimony, 
.  122 
00523 
6-38 
Mercury  . 
.  200 
0-0319 
6-38 
Aluminium 
.     55 
0-2143 
11-74 
Iron    .     . 
.  112 
0-1138 
12-74 
Would  it  not  seem  that  the  numbers  in  the  fourth  column 
are  too  variable  to  serve  as  a  foundation  for  the  determination  of 
"  combining  numbers  ?  "  It  is  true  that  Dr.  Wright  would  ex- 
cept oxygen  and  chlorine  from  this  list  on  account  of  difference 
of  physical  condition ;  but  what  about  the  other  numbers,  which 
vary  from  1*76  to  12*74  ?  Examples  are  not  needed  to  show  the 
fallacy  of  relying  upon  this  fact  alone  for  the  determination  of 
atomic  weights ;  its  use  consists  in  deciding  between  equivalent 
weights  and  multiples  of  those  weights. 
Dr.  Wright  says  that  "  the  term  combining  number  is  ex- 
tended  to  relative  numbers  approximately  equal  to  ~^~"     What 
is  this  but  an  admission  of  the  worthlessness  of  his  rule ;  for  in 
the  determination  of  such  number  approximations  are  not 
sufficient  ? 
In  assigning  to  oxygen  the  " combining  number"  16,  the 
author  admits  that  in  no  compound  do  less  than  two  equivalents 
of  that  element  exist ;  that  is,  that  that  weight  of  oxygen  is  indi- 
visible. In  the  same  manner  he  allows  the  twelve  parts  by 
weight  of  carbon  to  be  indivisible.  But  the  admission  of  indi- 
visibility is  at  the  same  time  an  admission  of  the  existence  of 
atoms,  which  he  professes  to  dispense  with,  or  to  regard  as 
unnecessary.  The  notion  of  atoms,  however,  cannot  be. unne- 
cessary if  Dr.  Wright  is  obliged  to  make  use  of  it,  as  it  is  evi- 
dent he  is. 
Dr.  Wright  defines  a  radical  to  be  "  one  or  more  symbols  and 
suffixes  transferable  from  one  formula  to  another;"  and  in 
another  place  he  says,  athe  passage  of  a  given  quantity  of  elec- 
tricity through  an  electrolyte  causes  the  evolution  of  equivalent 
quantities  of  the  radicals  into  which  it  decomposes  the  electro- 
lyte, no  matter  what  be  the  nature  of  the  electrolyte."  What 
does  the  author  mean  by  equivalent  quantities  of  an  assemblage 
