;( 616 ) 



purified by sublimation. Both Todohenzoic acids tims obtained were 

 tlien esterified by means of methyl alcohol and HCl. 



The product so obtained was purified by repeated recrystallisation 

 from boiling alcohol until the melting point became constant at 114°. 



The methyl ester oi' p-Iodobemoic acid m.p. 114° crystallises from 

 ether -|- alcohol in colourless needles, having a faint odour of aniseseed 

 oil, which are very neatly formed, and exhibit the form of fig. 8. 



Ehombo-bipyraviida I. 



a:b:c = 1,4144 : 1 : 0,8187. 



Forms observed ; a = jlOOj, predominant, very strongly- lustrous, 

 sometimes with delicate, vertical stripes; p = {210j, very sharply 

 reflecting; 6^jllO|, narrow, often absent, but yields very sharp 

 reflexes; w = il22j and r = \011\, well-developed; o = |112}, very 

 small and often absent altogether. 



Habit: flattened towards jlOOj, with tendency parallel to the c-axis. 



Angular measurements: 



Measured: Calcidated: 

 a:p = (100) : (210) =:*35°15V; — 



b:v = (010) : (122) =*51 49 — 



b:p = (010) : (210) = 54 447, 



v:v = {n2):{l22) = lQ''2Z' 76°22' 



/; : r = (010) : (Oil) = 50 24'/, 50 41'/, 



a:v = (100) : (122) = 77 29 77 23 



v:v=:(122):(Ï22)r=25 42 25 41 



r:r = (Oil) : (OTl) = 79 12 79 11 



v:r = (122) : (Oil) = 12 50V, 12 37 



p:r= (210) : (Oil) = 68 23 68 33 



?; : = (122) : (J 12) = 17 0'/, 16 43'/, 



o:o = (112) : (112) = 43 3 42 55'/, 



Cleavable towards |010j. 



The optical axial plane is jOOlj with the 6-axis as first bissectrix. 

 The apparent axial angle in «-monobromonaphthalene is about 80°; 

 the dispersion is Q <Cv. On a, p and b orientated extinction. 



The sp.gr. of the crystals is: 2,020 at 10°; the equivalent volume 

 — 129,7. 



Topic axes x : V' : « = 6,8179 : 4,8203 : 3,9464. 



From the above it follows that the /-compound is perfectly iso- 

 morphous with the analogous i?r-compound. By way of comparison 



