Abstract: An apparatus and method for calculating gamma radiography variables is provided. The apparatus includes a base with a circular logarithmic time scale displayed thereon, a first disk concentric and rotatably coupled to said base for displaying a circular logarithmic radiation source scale and a circular logarithmic source-to-film distance scale, a second disk displaying a circular nearly linear steel thickness scale and a radial tick mark F, and a third disk displaying a radial baseline mark and a plurality of film type marks. The method disclosed allows calculation of exposure time from known quantities: film type, source-to-film distance, steel thickness, radiation source type and strength.

Abstract: A pocket-sized, electronic gestational calculator includes a housing sized and shaped to fit into a user's pocket, an input device connected to the housing and configured to produce signals in response to actuation of the input device by the user, an electronic processor positioned in the housing and configured to receive the signals from the input device and to process the signals to produce gestational information, and a display connected to the housing and configured to display the gestational information produced by the electronic processor. Gestational information produced and displayed includes the expected due date and the gestational age in weeks, months and trimesters.

Abstract: A pocket tide calculator is described which predicts tide times and moon phases in a visual display which gives the semi-diurnal tide times in any given day of the month and can be readily set for the following month. This device automatically leaves out the high or low tide which is alternately missing every 7.5 days. This invention incorporates a compressed time scale when compared with a normal 24-hour clock face which enables a concise display of the semi-diurnal tide cycle.

Abstract: An alignment calculator circular slide rule device and associated method for determining shimming requirements for a drive unit to be coupled with a driven unit in angular alignment therewith. The circular slide rule device utilizes drive unit support separation data, coupling structure diameter, and measured angular offset values, to determine shimming requirements for angular alignment of the drive and driven units, by shim addition or removal to the supports of the drive unit.

Abstract: A golf round timing device is provided for determining the time at which a golfer is to start a golf hole. The golf round timing device comprises a base and a circular disk member. The base has an outer arcuate row of indicia, indicative of time intervals, disposed thereon. The circular disk member has a smaller radius than the outer arcuate row and is rotatably mounted at a mounting point on the base in such a fashion as to be concentric with the outer arcuate row of indicia. The circular disk member has at least one inner arcuate row of indicia indicative of holes on a golf course so that when the inner arcuate row of indicia is aligned with the outer arcuate row of indicia, the time at which the golfer is to start a golf hole may be determined.

Abstract: A disk is mounted upon a substrate of sheet material with a separate piece also of sheet material secured to the substrate and having at least a pair of strips overhanging the disk and of a length sufficient to lie flat thereagainst. The strips define a number of points at which the inner circumference of the disk is engaged and with a spacing a=Dsin (180.degree./n).+-.25% where D is the diameter of the opening and n is the number of disk overhanging strips. When two strips are provided the applicable formula is a=Dsin (180.degree./4).+-.25% where D is said diameter of said opening.

Abstract: A new device including a new arrangement of dive tables is disclosed for planning non-decompression dives. The invention utilizes two separate scales, movable relative to one another. The first scale shows the pressure group scale, the bottom time or residual nitrogen scale and surface intervals aligned by relationship to pressure group. The second scale shows depth scales, repetitive dive group, pressure group, and no decompression time limits scale. Windows in the second scale allow the observation of pressure group scales and corresponding bottom time on alignment of bottom time from scale one with depth from the second scale.

Abstract: A rotatable wheel assembly which is suited for use as a wheel calculator, including a wheel having an axial hole therein and bearing indicia on one of its faces, front and back covers between which the wheel is sandwiched, the front cover having a window opening therein for selective viewing of the indicia on the wheel face, and the back cover and the front cover being adhesively bonded to each other through the hole in the wheel, the bond providing a grommetless pivot or axle for the wheel. To inhibit contact between the adhesive bond and the wheel while maximizing the width of the axle relative to the size of the hole in the wheel, a mask having a hole therein which is of substantially the same size as, but not greater than, the hole in the wheel, is interposed between the back cover member and the wheel with the two holes axially aligned with each other.

Abstract: The amount of recording time remaining on a partially recorded videotape cassette (11) is measured by fixing the position of a body member (17, 117) relative to the hub (14) of a cassette reel, and moving a pointer (24, 120) to point to the outermost layer (33) of tape (12) wrapped around the hub (14). Movement of the pointer relative to the body member causes corresponding movement of an index (38, 145) relative to a time scale (39, 125), so that the remaining time can be read off the scale. The pointer is coupled so that small movement of the pointer relative to the body member, causes large movement of the index relative to the scale. In one embodiment, a transparent disc pointer (17) is coaxially attached to a transparent disc body member (24).

Abstract: An apparatus for identifying the optimum jet for a carburetor which includes a general annular first member having a plurality of first graduations disposed about a peripheral portion thereof, a general arcuate second member having a plurality of second graduations disposed for cooperation with the first graduations, and members coupling the first and second member permitting relative rotation and selective alignment of the first and second graduations. One of the plurality of graduations are arrayed on a linear scale corresponding to relative air density and the other of the plurality of graduations being arrayed on a scale corresponding to respective jet flow and or identifying numbers. The members coupling the first and second members may include a plurality of arms disposed at angularly space intervals. There may be three such arms and they may be fixed to the arcuate member. The annular member may include an offset peripheral portion that is nested between with the three arms.

Abstract: A calendar date finder in the form of a circular slide rule composed of two interacting disks, rotation of one disk relative to the other selectively providing calendar date information from a first preselected year through a second preselected year, inclusive. An upper disk has a circular periphery with a notch along a portion thereof, and further has a cut-out spaced uniformly from the periphery and extending along a portion of the periphery. Numeric indicia are printed on the upper disk adjacent the notch. The numeric indicia are sequential numbers from 1 to 31 representing the thirty-one days of a calendar month. Month indicia are printed on the upper disk in a predetermined pattern adjacent the cut-out. A lower disk has week day indicia printed thereon uniformly spaced along the periphery thereof, in a sequential pattern. Spaced inwardly from the week day indicia is a predetermined pattern of year indicia indicating each year from the first through the second preselected years, inclusive.

Abstract: Disclosed are various embodiments of a musical reference apparatus for use by musicians to rapidly and easily transpose or modulate music. The invention is preferably formed of two or three disc-shaped members which are rotatable relative to one another about a single axis. These disc-shaped members have musical indicia marked on upper surfaces thereof near their peripheries. The outer of the disc-shaped members has symbols thereon which represent musical tones, as does the inner of the disc-shaped members. An intermediate member which has symbols representing musical indexes can also be provided. Alternatively, the inner member can have two sets of symbols marked thereof, one representing musical tones, and the other representing musical indexes. Any of the various embodiments of the musical reference apparatus can be mounted on a reference card or on a wristwatch type device.

Abstract: A hand operated calculator is provided for estimating a length of a patch cord necessary to extend between any two of a plurality of connection locations of spaced apart frames in a distribution bay. The calculator includes three members which are movable relative to one another. Each of the members carries various indicia which when aligned indicate an optimum amount of patch cord necessary to extend between indicated connection locations of spaced apart frames.

Abstract: A concentric rotating disc assembly includes a pair of outer discs and an intermediate disc. The intermediate disc rotates about a journal which is die cut from the center of the intermediate disc with each face of the journal adhesively secured to an inner face of an abutting outer disc. The assembly is fabricated from a rectangular paperboard blank having parallel fold lines which divide the blank into three square panels. Score lines are provided in each panel to define its respective disc and a central circular score line in the intermediate panel defines the periphery of the journal. When the panels of the blank are folded along their fold lines in a predetermined order, the panel carrying the intermediate disc is positioned between the panels carrying the outer discs and all discs are concentrically registered.

Abstract: A device for assisting a computer operator in the use of computer programs includes relatively movable cards bearing data areas thereon arranged in such a way that the operator can, firstly, by visual inspection, readily locate the desired operation to be performed by the program and, secondly, by moving the cards relative to one another, obtain, for that desired operation, information regarding the command to be entered into the computer.

Abstract: A fluoride supplement calculator utilizes two concentrically positioned relatively rotatable disks. A front disk has a plurality of fluoride level apertures which overlie groups of fluoride dosage amounts carried on the second disk. An age scale is also placed on the obverse surface of the second disk. The second disk has a single aperture which is used in conjunction with the reverse surface of the first disk to depict fluoride uptake and enamel formation in teeth of patients of various ages.

Abstract: Disclosed is a diving computer in the form of a circular slide rule for aiding a SCUBA diver in planning one or more dives within a short amount of time, including more than one depth per dive, so that the diver may avoid risking decompression sickness. The computer has two faces, one of which calculates the increase of pressure within body tissues during a dive and the other of which calculates the decrease of this pressure after surfacing. The result of one side's calculation is used as the initial value for the other side's calculation, permitting the diver to track net residual pressure over a series of rapid repeated and/or multiple-level dives, and by so doing, avoid excessive tissue pressures that might cause decompression sickness.

Abstract: An alcoholic concentration indicator comprising three superposed circular discs adapted to rotate about a common axis. The lower disc displays on its margin a scale of alcohol concentration indicia and over its central surface a multiplicity of numbers representing the number of drinks consumed. The middle disc has a series of aperture across a diameter to provide usual access to the numbers appearing on the central portion of the first disc. Each aperture is identified by a weight of a human body. A scale of consecutive numbers also appears to represent the number of hours elapsed since the first drink. The top disc is transparent and displays two pointers: one pointer for the alcoholic indicia and the other pointer for the time elapsed since the first drink. The desired results are obtained by visualizing the number corresponding to the number of drinks through the aperture corresponding to the weight of the user.

Abstract: Apparatus for use in correlating actual tape play times, tape length, or predetermined tape program locations with tape-spool revolution values provided by a tape-revolution index counter in a tape machine. The calculator has a lower circular base plate and a smaller, upper circular plate which rotates concentrically with respect to the lower plate. The base plate carries a scale corresponding to tape-spool revolution values indicated by the machine, and one or more time scales relating tape spool revolution values to actual tape-play times, and/or to remaining play times or program locations. A ratio marker and time scale indicator are positioned on the upper member such that alignment of the ratio marker with a selected tape-revolution value on the base plate brings the time scale indicator into alignment with the corresponding playing-time value on the base plate.

Abstract: A time period calculator employing a base, a calendar disc, a calculation disc and a cursor. The calendar disc includes divisions identified by months and days of the year about a common axis. The calculation disc is divided into increments of time in days, weeks and months from zero consecutively in both clockwise and counterclockwise directions for measuring time periods prospectively and retrospectively, respectively. The base may include divisions divided into 1/365th segments with day of the week indications thereon. The cursor includes line segments offset over the calendar disc divisions by one day so as to accommodate leap year calculations.

Abstract: A vehicle performance computer for determining the performance parameters of a vehicle including: a substantially planer base having logarithmic scales representing speed, weight-to-horsepower, distance, and time arcuately disposed about a center; a substantially planar intermediate slide having logarithmic scales representing percent grade, speed factor, and top time and distance percent grades in proporation to the percent grade scale and arcuately disposed about a center; and a substantially planer top slide having logarithmic scales representing speed factors in relation to time and distance scales and arcuately disposed about a center. All three planer members are rotatably connected one to another coaxially about the three centers with the intermediate slide lying between the base and top slide. The intermediate scale also includes a window arcuately disposed about the center for viewing the weight-to-horsepower scale in relation to the percent grade scale.

Abstract: The Heat Stress Calculator is a manually operated, mechanical computer and program for determining human thermal discomfort or heat stress, reported as an equivalent heat stress temperature (HST), for any given summer air temperature, relative humidity, wind velocity, sky condition, time-of-day, terrain, and individual physical activity level. The calculator consists of six circular and partial discs concentrically mounted for adjustment of their scales by rotation to various positions relative to each other and to stationary front and back windowed panels. The Heat Stress Temperature is the equivalent air temperature under standard moderate thermal and activity conditions that would result in the same heat stress produced by the actual conditions experienced.

Abstract: A calorie counter for persons wishing to control their weight having a housing with a base and a transparent cover rotatably mounted to the base. An opaque partition is located in the housing parallel to the cover and spaced apart therefrom. This partition has three circular calorie counting scales provided thereon. The partition consists of an inner disk having first and second calorie counting scales and an annular disk which is an outward extension of the inner disk. The annular disk is rotatable and protrudes through a side wall of the base at one location. Two line indicators are provided by two transparent disks located between the cover and the annular partition. The first indicator points to the number of calories contained in a food item while the second indicator points to the total number of calories consumed by the user during a set time period. A gear mechanism operated by a thumb wheel operates both of the indicator disks at the same time.

Abstract: Apparatus for determining the levels or echelons of a multi-character code f a supply source, maintenance and recoverability (SMR) code for component items in a parts inventory for military equipment comprising a circular code wheel including a first circular member in the form of a disc having first and second faces respectively divided into indicia bearing sectors the outer perimeter of which identify a particular character position of the code.

Abstract: A slide-rule is obtained by superpositioning and connecting three plates (1, 2, 3) into the middle one of which slots (20, 21) are milled, and thereafter cutting off the boundary areas (5, 6, 7, 8), including the boundary areas (5, 6) of the middle plate (2), into which the slots (20, 21) do not extend.

Abstract: This invention is a calculator that is particularly adapted to assist the user thereof in determining the location of waterfowl decoys relative to a duck blind. The calculator can be adjusted as wind direction dictates to give varying patterns under varying wind speeds and directions.

Abstract: A slide rule for solving time/speed/distance problems where distances are measured with a single or universal ruler applicable to all charts or maps regardless of scale. Result is achieved by printing alongside time entries on the slide rule a row of appropriately-spaced numbers constituting indicia of chart or map scale, and which has a range encompassing the largest and smallest scales of charts or maps which are likely to be encountered. When such numbers are properly positioned, it is necessary only to set chart scale opposite speed made good, after which running time will always appear opposite distance travelled, and vice versa. This device eliminates the need to use dividers and mileage or latitude scale, and thus obviates the intermediate steps which their use entails.

Abstract: A convenient, easy-to-use calculator computes a person's proper bra and cup size given a knowledge of that person's chest, overbust, and band measurements. The calculator comprises a circular slide rule of three superimposed disks, the intermediate disk being of larger diameter than the upper disk and the lower disk being of larger diameter than the intermediate disk. The three disks are mounted for relative rotation by means of an axially disposed pivot, pin, rivet, or other means transfixing the disks for ease of rotation about their centers. Scalar indicia at the periphery of the disks represent body measurements required for the determination of proper bra size. Proper bra and cup size are viewable through circular indexes when a person's chest and overbust measurements are aligned on the two outermost peripheral scales and the person's underbust or band measurement is aligned with a fixed index on the intermediate disk.

Abstract: A method of fabricating a hand calculator utilizing die press punching to form its three parts. A circular stationary base plate is punched with a central, circular, raised, beveled portion which is then rigidly fixed to a circular stationary top plate by means of flared eyelets. Between these two parts a circular movable scale plate is movably inserted. The scale is etched with scales, and punched with a plurality of holes about its periphery to allow for pencil point movement.

Abstract: A color computer wheel includes a white base member upon which four concentrically arranged discs are rotatably mounted by a central fastener, the discs decreasing in diameter from bottom to top and being made of a transparent sheet material. The top disc carries four concentric annular bands, each evenly divided into radial spaces. The three lower discs are each dedicated to a single primary color, and carry color bands arranged to register with the bands of the topmost disc, the color bands being divided evenly into radial spaces with progressive color shades thereon. The peripheries of the four discs carry legend strips, which identify the percentage of color in the radial spaces in alignment therewith.

Abstract: A calculating rule for obtaining ophthalmic values which are necessary for making eyeglasses, such as near-point distance, far-point distance, visual range, and addition, especially by which the eyeglasses-wearer can continue his work at the objective working distance with no asthenopia based on accommodation, from other ophthalmic values such as power of the ametropia, accommodation, etc., and for obtaining the resultant prism-diopter and base-direction of the prism for correcting heterophoria.

Abstract: A device is provided for measuring a subject's reaction to stimuli, i.e., to measure a subject's indication of attitude, opinion, judgement, preference, evaluation, feeling, intention, etc. when presented with a question, problem, fact, situation or other stimuli the subjective response to which is sought to be measured, said device comprising a first means having a defined viewing area and a colored means having at least one colored area adapted to be viewed in said viewing area wherein the extent of colored area viewable is variable and adapted to indicate the degree of a subject's reaction to a specific stimulus.

Abstract: A calculating device and a method of use thereof for determining the lead required to shoot a projectile at a moving target including cooperating logarithmic scales with indicia corresponding to the parameters target speed, range, projectile speed and lead displayed on a fixed and a slide member. Pictorial markers representative of various projectiles are disposed along the projectile velocity scale at locations corresponding to their normal speed and words descriptive of target speed are disposed at appropriate locations along the target speed scale so that calculations may be made by persons not having knowledge of game and projectile speeds in numerical terms. In accordance with one embodiment of the invention, the logarithmic scales are longitudinally disposed and the slide member may move relative to the fixed member in a horizontal direction. In accordance with other embodiments of the invention, the scales are disposed in a circular arc on members which may be rotated about a common axis.

Abstract: The rotatable wheel assembly includes a wheel member rotatably sandwiched between a pair of cover members. Grommetless securing means are provided on at least one of the cover members for securing it to the other cover member through an axial opening in the wheel member. The grommetless securing means, which in one embodiment constitute an adhesive patch formed on at least one of the cover members, also function as a pivot for rotation of the wheel member with respect to the cover members. In other embodiments of the invention, the grommetless securing means comprise an adhesive patch member, which can be formed as an appendage to one of the cover members, that spans an opening in one of the cover members to adhere to the other cover member through the axial wheel opening.

Abstract: The Camera Setting Calculator for Underwater Color Photography is a manual, mechanical calculator to be used in determining the aperture setting (f-number) of a camera and consisting of two circular sheets of data pivoted to rotate over each other. Rotation of the top piece inputs the given data and displays the appropriate f-number.

Abstract: A hand-operated musical rhythm pattern generator includes two independently rotatable discs mounted in a holder. The discs have complementary rhythm patterns printed on the peripheries thereof, a portion of which is visible through a window in the holder. The rhythm patterns displayed may be randomly changed by rotating one or both discs any desired angular amount.

Abstract: A circular slide rule type calculator is disclosed for calculating various parameters useful in determining operating characteristics of an air conditioning or refrigeration system. A series of four discs each having scales are used to calculate power consumption, load and part load performance factors.

Abstract: A calculating device and a method of use thereof for determining the lead required to shoot a projectile at a moving target such as game including cooperating logarithmic scales with parameter indicia corresponding to the range of the target, the speed and direction of movement of the target, the speed of the projectile and the required lead displayed on a fixed and a slide member. Markers representative of various projectiles are disposed on the projectile velocity scale at locations corresponding to their normal speed and words descriptive of game speed are disposed at appropriate locations along the target speed scale so that calculations may be made by persons not having knowledge of game and projectile speeds in numerical terms. The lead is calculated from a knowledge of the parameters in a two step process of moving one member relative to the other. In accordance with one embodiment of the invention, the scales are arcuately disposed on members which may be rotated about a common axis.

Abstract: Method and apparatus for copy-fitting, using a new parameter called Font ID in a circular calculator having a plurality of relatively rotatable disks, some of which have cursors affixed thereto, and one or more freely rotatable cursors. Scales on the several disks include Font ID numbers, type size, in points; line length, in picas; number of characters per line; number of characters per page; page depth in picas and number of lines; and line spacing in points.

Abstract: A mechanical calculating device is provided which is particularly useful in determining the relationship of the heavenly bodies to specific heavenly positions at different times. The device, in the embodiment to be designed, comprises a base, a first disc rotatably mounted on the base, which has inscribed about its periphery a ring scale divided into twelve sectors each marked with a different Zodiacal sign, and each sector is subdivided into thirty indices each representing one degree of arc. A plurality of transparent discs are rotatably mounted on the base in concentric relationship with one another and with the first disc, the latter discs representing the sun, the moon and the various planets. The latter discs are each provided with an identifying tab, and each is inscribed with a series of lines extending outwardly from a common point adjacent to the tab at selected angles to one another, with each line having a selected color.

Abstract: A circular disk type calculator for determining the proper approach speed for a particular aircraft within a specified range of gross weights and flap settings. The calculator includes three superposed circular disks pivoted for independent rotation about their centers. A third lower disk is imprinted with appropriate speed and weight information. A second intermediate disk includes cut-outs and windows to expose certain readings on the lower disk and also includes a flap setting marker extending outwardly from its outer edge. A first upper disk is provided with appropriate windows and markings relating to the other disks thereby indicating the desired information including pattern and threshold air speed for the gross weight and flap setting of the aircraft.

Abstract: An improved circular sliderule for use in many applications wherein it is desired to provide a sliderule having superimposed disc elements which may be freely rotated without disturbing the previous setting of the adjacent discs. The novel improved calculator comprises providing a separating spacer element to be positioned between each disc of the calculator and with each spacer element having formed thereon means for retaining the rotation of the spacer element whenever superimposed discs are rotated. The retaining means may comprise a series of protruding arms, one extending outward from each of the separating spacer elements, joined at their outer ends and locked to the base plate of the calculator which is not rotatable. Alternately the retaining means may comprise the spacer element having formed on an internal hole at least one protuberance which is designed for mating engagement with an engaging means in the form of an elongated slot formed in the central hub which is locked to the baseplate.

Abstract: An adjustable display having interworking parts whereby upon manipulation interference frequencies emitted from spurious harmonic and imaged electromagnetic radiators interfering with an intended or expected bracketed received frequency can be isolated and identified for later corrective action, such as elimination of the interference frequencies. A method for establishing emitted frequencies which might interfere with expected or intended targeted received frequencies in a receiver is also described and taught.

Abstract: Calculating device provided with scales for calculating radioactive doses and intensities, in which the scales are arranged for calculating the product of the intensity in a radioactive area at a given instant and a dose factor to be determined by experiment. This dose factor depends on the moment when the contaminated area is entered and on the time spent in the area.

Abstract: A hand-held weight control calculator which allows an individual to quickly and accurately determine the daily maximum food calories allowed for either maintaining body weight or for losing a particular number of pounds as a function of individual weight and activity level. The calculator includes a first indicia bearing disc having a plurality of radially arranged columns displaying daily calorie values disposed on its surface, with each column having a peripheral heading designating an individual weight range value and a registration arrow. A second smaller diameter disc is affixed to the center of the larger disc so that they rotate relative to each other, with the smaller disc including an observation window which is selectively registrable with a particular radial column disposed on the larger disc.

Abstract: Daily engine checks or health tests are being developed for determining the ondition of an engine by relating significant performance parameters. One such health test, termed "HIT," utilizes exhaust gas temperature along with compressor speed. Since results of this test vary with outside air temperature conversions must be made by maintenance personnel and pilots. A calculating device is provided for this use.

Abstract: A global time system having a first disc divided into twenty-four equal sections, each section being formed by lines extending radially from the center of the first disc. Each line forming the sections representing a line of longitude. Circles are concentrically disposed about the center of the disc and extend outward to the edge of the disc. The circles, representing lines of latitude, cross over each of the twenty-four lines of longitude to form geographic spaces between the lines of longitude and latitude. A time disc is rotatably mounted to the center of the first disc and has twenty-four lines equally spaced from each other on the outside edge. Reference symbols are positioned on the first disc and adjacent to the outside edge of the time disc, with the reference symbol in each of the twenty-four sections. Identification symbols representing a specific geographic location are disposed within the respective geographic space having the proper longitude and latitude of the location.

Abstract: A circular slide rule is provided suitable for use in a method determining the electrolyte deficiency in the extra-cellular space from the measured electrolyte deficiency per volume of serum, body weight and body height, and is a method of determining electrolyte deficiency therewith. The circular slide rule comprises a basic disc, a centrally rotatable first rotary disc supported on one side of the basic disc but having a smaller diameter than the basic disc and a centrally rotatable second rotary disc supported on the side of the basic disc opposite to that of the first rotary disc but having a diameter smaller than that of the basic disc. Substantially straight cursors are also provided, each being rotatably supported on one of the rotary discs relative to the appropriate rotary disc and with respect to the basic disc, each said cursor extending at least to the circumference of the basic disc.

Abstract: An elapsed time display and reminder device that is manually adjustable by the user to select a time in the future that may be many days in advance of the present, and to provide a calibrated countdown display of the progressively diminishing time interval until the selected future time is reached. In a preferred device, the user enters the present time and the future time in calendar form as a month and day of the month, and the device automatically converts this future calendar date less the present date, into an elapsed time interval as a number of days.

Abstract: A laser system computer in the preferred form of a hand-holdable, two-sided circular slide rule, for quickly and accurately solving a wide range of problems which are associated with laser radar, designation, communications and directed energy applications, the solution of which said problems could not be attained with prior art slide rules of any type. Calculations relating to the design, analysis and performance of lasers are performed on one side of the calculator. Atmospheric effects, such as attenuation and turbulence beam spreading, are computed on the other side of the calculator. Both continuous wave and pulsed lasers can be calculated with the use of this unique computer, which also may be used for ground, air and space laser applications. Structurally, the preferred embodiment is in the form of a circular slide rule having: a circular stator (i.e., base) with a front face and a rear face; a plurality of concentric discs (i.e.