497 



of A^^ -|- A," foi' tiie different combinations of h^ and A, ranged in 

 the succession of increasing values of A," -|- A/. On comparing this 

 series of values of A/^ -\- A./ with the ninnbers of the sixth column, 

 the index-ti-i[)les with A, = 0, given in the seventh column (not primed 

 in italics), ai'e found to satisfy. By adding 6 to all the values of 

 A/^ -|- /// and comparing again with the numbers of the sixth column, 

 in the same manner the index-triples witli A, =r 1 of the eighth 

 column are found. In a similar manner the ninth and tenth columns 

 are composed. 



Apart from the tirst four lines, in connection with the 

 deviations which exist for the small values of 6 (comp. p. 498), of 

 the remaining 19 lines, there are only 2, which do not belong to 

 index-triples (not printed in italics), of which not all the indices are 

 either even or odd. On considering whether all the lines to he expected, 

 which fulfill this condition, are present, it appears that 5 of them 

 still ought to appear. The index-triples meant here, are collected 

 and printed in italics (columns 7 — 10) and assigned to those lines, 

 of which the place is nearest to the place expected foi- these lines. 



The difference between the places, where these lines are found 

 and those, where they would be expected, is in all those cases 

 minute, and can ibr two cases be ascribed to the fact, that the line 

 meant, cannot be seen separated from a neighbouring line and in 

 all cases does not exceed (in connection with the small value of A) 

 the uncertainty of observation. 



There is evidently indication enough for accepting a structure 

 that is in accordance with the exclusive occurrence of interference- 

 lines, which must be ascribed to reflections on net-planes with 

 only even or only odd index-triples. 



The absence of index-triples of which not all indices are either 

 even or odd, points to centered sides. 



From the atomic weight (119,0), the specific weight at 18° C. 

 (7.285j, AvoGADRo's number (6,06.10") and the wave-length of Cua^: 

 (1,541,10-8) follows with .4 = 0,01734 and ^ = 6,06 ') (which 

 value later on appeared still better to satisfy than 6), for the number 

 of atoms per cell the value 3,02. 



Now, we come to the number 3 by placing atoms in the corners 

 of the cells and in the centra of the prism-faces. 



') [Note added (lining translation]. By a somewhat different method of calcu- 

 lation A- J. BiJL, i.e. p. 33 obtained the value 5.988. This fact points to a greater 

 probability of (/ = 6 accurately. In this case the projection of all the net-points on 

 a diagonal-plane through the smallest edge of the elementary. cell would be a net 

 of equilateral trianj^les with side 2,37. l()-8 cni. (Comp. A. J. Bi.iL, I c. p. 34). 



