( 80 ) 



It is monocUno-prlsmatic; the crystal parameters were calculated to be: 



a:b:c — 0,8476 : 1 : 0,5092 



^=70°42'. 



Forms observed: a = jlOOj, strongly predominating; ?7i = jllOj 

 and 6 = jOlOj, very narrow; c = |001|, very small and less con- 

 spicuous; q — \Oil\ and 6'=|021| equally broadly developed. 



*a : m = (100) : (110) = 38° 39V; - 



*a : q=:: (100) : (Oil) =: 72 40 — 



^c : q = (001) : (Oil) = 25 40 — 



s : 5 = (021) : (Oil) = 18 18 18° 12' 



b:m = (010) : (110) = 51 20 51 20V,. 



A distinct cleavability was not found. 



Therefore, benzyl pi Ltalimide is dimorphous. As regards the remarkable 

 connection of this /^-modification with the crystalline form of the 

 iso-imide and with that of the «-modification, see the end of this 

 article. 



c). Benzylphtal-iso-imide. (m.p. 8272°)- 



The crystals represented in Fig. 3 have been 

 obtained from anhydrous ether; they are long- 

 prismatic and here and there of a porcelain 

 white. After some time, even if kept in the dark, 

 they become quite opaque and look as if they 

 were effloresced. The crystals, however, do not 

 contain any co-crystallised solvent ; probably some 

 transformation as yet unknown, has taken place 

 here. 



The symmetry is monocUho-prismatic ; the axial 

 elements, when choosing the following elementary 

 forms, are calculated to be: 

 Fig. 3. a : b : c = 1,2303 : 1 : 0,5932 



^=71°46'. 

 Forms observed: /?i = |110|, strongly predominating; c = 1201|, 

 also well developed; r=|001|, fairly strongly; ^ = |011|, very 

 plain ; a — |100| narrower ; b = |010| very narrow ; between r and 

 c there is still an orthodoma |hOk|, which Avas very little developed 

 and could not be measured. I have retained the above letters for 

 the notation of the forms, because the habitus of the crystal renders, 



