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It is shown that the double lens probe‐type electron diffraction camera described earlier is capable of producing useful electron diffraction patterns of single microscopic crystals in the size range 200–2000A; the formation of an opaque carbonaceous deposit, which occurs when an electron probe is focused on a specimen, is prevented in the diffraction camera by previously exposing the specimen chamber to an electron spray. A number of examples of two‐dimensional grating patterns and Kikuchi‐line patterns obtained from such crystals are shown. From either type of pattern it is possible to obtain accurate values for some of the lattice spacings, while from the Kikuchi‐line patterns it is possible to deduce accurately the orientation of the crystals relative to the electron beam. The results are shown to agree reasonably well with the predictions of the dynamical theory as presented by MacGillavry. It is concluded that a two‐dimensional grating pattern is to be expected from a crystal oriented with an important lattice vector approximately parallel to the electron beam independent of slight disorders or warping of the crystal. Kikuchi‐line patterns are to be expected for most other crystals which are not excessively thick or disordered. The theory also shows that both types of patterns may be obtained simultaneously.