ON COLOURING MATTERS. 63 
_ The lime compound gave the following results :— 
I. 0°4685 orm. gave 0°2065 sulphate of lime, equivalent to 0°0857 lime. 
~ IL. 0°4750 grm. gave 0°2125 sulphate of lime, equivalent to 0°0882 lime. 
_ Assuming that the formula for this compound is C,, H, O; + Ca0+HO, 
i Found 
; Sai Calculated 7 
- Numbers. 7 TT 
1 eq. Alizarin ...... 112 74°91 
Ager NVIALETS 5 pie’ 0p: sehr 9 6°03 
ast LaTC xe ero e: sige oO 19°06 18°30 18°58 
y 149°5 100:00 
_ The baryta compound gave the following :— 
 0°2450 grm. gave 0°1420 sulphate of baryta, equivalent to 0:0932 baryta. 
_ Assuming that the formula of this compound is similar to that of the last, 
viz. C,, H, O, + BaO + HO, its composition would be as follows :— 
Be Calculated. Found. 
Pay Alivaring ye viele s 112 56°65 
DR POWVIATED UGE dis i Rieintels 3 9 4°57 
Poy) Barytas 62s... RE Oat M7169 68 _ 88°78 88:03 
197°68 100°00 
Neither of these compounds loses the equivalent of water which it contains 
~ on being heated in a water-bath for several hours. 
_ The composition of crystallized alizarin must therefore be as follows :— 
Calculated. 
14 eqs. Carbon ...........06- 84 56°75 
Bigs.) | EAYETORCR. CE.» w.ci¢ sno. Ste os 5°40 
Nebsng: CRM MOU haley <n =< syelee * 8.) 40 37°85 
r 148 100:°00 
Calculated ue 
, Numbers. Sih tees 
1 eq. dry Alizarin .... 121 81-76 
3 eqs. Water ...s.0-5 27 18°24 18°33 18°32 
148 100°00 
it follows that alizarin dried at 212° must consist of— 
Calculated. 
Weeds, Carbo s oy t's ves. se ces 04 69°42 
Die) “RPVYOTOGGM. pis gees +06 «5's 5 4°13 
eo sa) CPR GOURMET eth oles sons) c's sO 26°45 
121 100:00 
mula of benzoic acid is C,, Hg O,, and alizarin only differs from it there- 
e by containing one equivalent less of hydrogen. If we compare alizarin 
isatin, we shall find that the latter only differs from the former by con- 
ing in addition the elements of one equivalent of cyanogen. The formula 
isatin is C,, H, NO, = C,,H;O,+C,N. Anthranilic acid differs in 
position from alizarin in containing in addition the elements of amidogen, 
the formula of anthranilic acid is C,, H, NO, = Cy, H; O, + NH,. 
* See p, 62. 
