records a small intersection with complete cones of diffracted bea.ms. Since there are inany cryst,als present io assort.nient of orientations at random, the diffraction takes place in all directions froin the speciincn producing cones. Since ordinarily w e find interest only i n angles, wc r~cordonly a small
nark as coiitrolling heat-treating of steel. Indeed, in that field tlie author has shown that in some matcrials tlie heat t,reat,ineiit may be accurately detcrtnincd from the appearance of the film. It is essentially a nondestriietive method, althongh, of course, one inust, at present, have a small portion of the material for examination rather than a very large onr. Even t,liis ~-equireinent could he elirriiiia.ted by certain desigii of eqiiipment. ACKK~WI,EUGMENT
I:r,;.
12-SOX.~ SOI.UTION IN A ~ i w n IKONA N O T N B I?FPSET
06
During the three years of work rvith X-ray diffraction tlic aut.lior has enjoyed the profit,ablc advice and criticism of his assoekte, A. 13. Gladding. This privilege is gratefolly acknowledged.
PLILCIIII.%-
rl"N
le ihc lower rpecimgrsm addition lines of conipiix arrriigemenl comespoiid io a crrnulix carbide developid b y annealing. The r i i i i i ~ i i a l is hi~ll.rpcudsteel.
ioii of the cones. For study of preferred oricntirtion we rcooril the enbire circular s f d o n of the COIICS on a Rat plat,c or film. TVlien the assortment of orientations of crystals in the q)eciincn is truly at ratvlom, t,hen the circles are cac!h uniforinly intensc at, all points, IVli
