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Induced stereoscopic motion, ISM, is apparent movement in tall static objects projecting from a reasonably flat background when viewed stereoscopically. ISM is produced by a smooth but extensive variation of the stereo-base (the separation of camera points) in a pair of moving picture films. The two films are projected by two separate but synchronized projectors onto rear view screens which are placed in the field of view of a stereoscope. In a controlled test it was found that subjects located targets faster and with fewer errors with ISM film than with comparable film in which the stereo-base was fixed at the maximum of the ISM film. This improvement of search is due almost entirely to searchs for targets which are difficult to find. Easy targets were always found and found quickly by both methods. ISM is as yet a laboratory production, but plans are being made for developing its field and applicability.

A binary number can be thought of as an alternate form of expression for either a set of letters or a decimal number. There are then three equivalent expressions, easily translatable to one another, each having difFerent characteristics. Four examples are given in which the form of on expression is chonged to an equivolent expression to save space or gain power. IntroductionWe have found binary numbers useful in routines that set up combinations. Four routines are given as examples. The binary number can be stored in several words, one binary digit to a word, i.e. a word is either 1 or 0. Although this manner of storage is wasteful of computer space, it permits the routines to be written entirely in FORTRAN. Another manner of storage is to pack binary numbers into words, 10 digits to a word. A binary number up to the equivalent of 1024 can be packed into a single computer word. However, operations upon single digits in a word are thus required and tliis calls for tbe use of symbolic machine language programming. We have for this purpose the PEST compiler^ for the IBM 7072, which enables us to use AUTOCODER inserts in a FORTRAN program. Examples 1 and 4 below show such usage.

A major problem in using the analysis of variance, as the number of factors increases, is the exponential rise in the number of interactions;. Even though the experimenter may not be interested in these interactions it is impossible to ignore them in most experimental designs because of the problem of getting error terms.It is natural therefore to look to the computer to handle the bulk of work involved in computing the interactions. A program device to get the computer to do this is described. Garber [2]. We use roughly the same line of reasoning as Garber in developing the basic computational routine. We then construct computer controls to carry out the routine for any number of factors, levels and data within computer limits. Generalized program plans for computing the analysis of variance have been reported by Hartley [1] and byThe data are considered as being on a single dimension, and they are controlled by a single index which runs from one to the total number of data, which we call NTOT. This method inw3lves somewhat different problems from the use of a data matrix of as many dimensions as there are factors, but it; permits an unlimited number of factors.The order of data in the single dimension is critical. In our work factors, or variables, are represented by single letters, which are assigned an arbitrary order in a left-toright list. Each factor can have any number of levels (conditions). The order of the data must be such that the levels for the first factor (leftmost letter) change most rapidly, the levels for the next factor change next most rapidly, etc. For example, let there be three factors, ABC, for which the number of levels are as follows: A-2, B-3, C-2. Then the data must be ordered as follows: 1 = a~b~c~, 2 = a2blcl, 3 = alb2cl, 4 = a2b2cl , 5 = a~b~c~, 6 = a2bacl, * Systems Engineering Department. i The starting value of the loop index is ml , the final value is m2 , and the increment is m3 .

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