42 Comparative Efficiency of different Forms of the Spectroscope. 

 Table 11.-60° Prisms. 







1 sur- 



1 



2 



3 



4 



5 



10 







face. 



prism. 



prisms. 



prisms. 



prisms. 



prisms. 



prisms. 



r 



Deviation ...< 



1-5 

 1-6 

 17 



18° 35' 

 23° 8' 

 28° 13' 



37° 10' 

 46° 16' 

 56° 26' 



74° 20' 



92° 32' 



112° 52' 



111° 30' 

 138° 48' 

 169° 24' 



148° 40' 

 185° 4' 

 225° 44' 



185° 50' 

 231° 20' 



282° 10' 



371° 40' 

 462° 40' 

 564° 20' 



Dispersion ..A 



1-5 

 1-6 

 17 



756 

 •833 

 •949 



1-512 

 1-667 

 1-899 



3023 

 3-334 

 3-797 



4-535 

 5000 

 5-696 



6-046 

 6-667 

 7-594 



7-558 

 8-334 

 9-493 



15-116 

 16-668 

 18-986 



Transmitted . < 



1-5 

 1-6 

 1-7 



•945 



•920 

 •888 



•895 

 •853 

 •801 



•811 



748 

 •681 



742 



•672 

 •608 



•686 

 •618 

 •565 



•641 



•578 

 •538 



•509 

 •491 

 •505 



Table III 



.—Angles of Prisms 67° 22', 64°, and 60° 56'. 







1 sur- 



1 



2 



3 



4 



5 



10 







face. 



prism. 



prisms. 



prisms. 



prisms. 



prisms. 



prisms. 



Deviation ..A 



1-5 

 1-6 

 17 



22° 38' 



26° 

 29° 4' 



45° 16' 

 52° 



58° 8' 



90° 32' 

 104° 

 116° 16' 



135° 48' 

 156° 

 174° 24' 



181° 4' 

 208° 

 232° 32' 



226° 20' 

 260° 

 290° 40' 



452° 40' 

 520° 

 580° 20' 



Dispersion ..A 



1-5 

 1-6 

 17 



1 



2 



4 



6 



8 



10 



20 



Transmitted A 



1-5 

 1-6 

 17 



•923 



•899 

 •874 



•863 



•818 

 780 



763 

 702 

 ■657 



•691 

 •629 



•588 



•639 



•582 

 •549 



•600 

 •552 

 •523 



•520 

 •505 

 •501 



To apply these Tables to an example, let us compare three 

 spectroscopes of ten prisms each, of angles 45°, 60°, and 64°, the 

 index of refraction being 1*6. 



10 prisms of 



Deviation. 



Dispersion. 



Transmitted. 



Trans. X cos i. 



o 



45 

 60 

 64 



305° 

 462 40 

 520 



9-680 

 16-668 

 20-000 



•3911 



•4912 

 •505 



•308 

 •294 

 •268 



Again, comparing spectroscopes producing equal deviation, 





Deviation. 



Dispersion. 



Transmitted. 



Trans, x cos i. 



o 



12 prisms of 45 

 8 „ 60 

 7 „ 64 



366 

 370 8 

 364 



11-616 

 13-334 

 14 



•339 

 •532 

 •521 



•268 

 •319 

 -276 





