associated  equipment  is  portable,  generally  inexpensive and very versatile, making it an excellent device for public   speaking   use.   Most   public   affairs   offices, especially  if  they  operate  speakers  bureaus,  have  a  good 35mm Carousel slide projector system. Slides  are  fed  to  the  projector  from  a  top-mounted tray designed to accommodate up to 140 slides. The slide tray accepts film sizes 126 (28 by 28mm), 135 (24 by 40mm) and 127(1 5/8 by 1 5/8 in.). Slides mounted in cardboard, glass, metal or plastic 2- by 2-inch frames up to 1/10 inch thick can be used. Slide identification numbers are molded onto the tray. As the tray revolves, the number of the slide being shown is opposite the gate index on the projector. The forward and reverse buttons located on the side of the projector control the direction of the movement of the slide tray. When you momentarily depress the forward or reverse button, the slides change in either direction  at  any  desired  time  interval.  A  wired  remote control has similar buttons and, inmost cases, a focusing lever for power focusing the lens. Some  units  are  equipped  with  an  automatic  timer feature. When the timer is set at one of three settings (5, 8  or  15  seconds),  the  slide-changing  mechanism  is actuated automatically and the slides are viewed for the number of seconds indicated. The timer feature may be interrupted at any time by using the forward and reverse buttons on the remote control or on the projects. Another feature of the Carousel projector is a choice of high or low illumination. In the high position, the entire  500-watt  illumination  of  the  projection  lamp  is selected.  In  the  low  position,  the  illumination  is decreased to 425 watts for longer projection lamp life. A  dissolve  unit  incorporating  more  than  one projector may be used to create a motion-picture effect. ACTUAL OBJECTS AND MODELS At times objects can be used to support your main points. They can be the actual objects you are speaking about  or  objects  that  can  symbolize  your  idea;  for example,  a  mechanic’s  hammer  and  a  sickle  can represent   communism. You must remember two things when using actual objects  as  visual  aids.  First,  the  objects  must  be  large enough so that all important details are visible, yet small enough to be handled by the speaker. Second, the object should not be displayed by holding it in your hands; set it on a table or use it on a hook and loop board. You can make models representing tangible objects to symbolize an intangible idea, and use them to support your  point:  for  example,  a  scale  to  represent  justice,  a small Statue of Liberty to represent freedom, and so forth. You can make models easily from cardboard, wood and string. Often with models, action can be built in to further enhance the impact of the aid. The same rules that  apply  to  objects  apply  to  models  displayed  in  the speaking  area. AUDIO OR SOUND EFFECTS Audio  devices,  when  used  in  conjunction  with visual aids, can further the impact of your presentation and increase the audience’s retention of your subject matter. In supporting your point, your audience must be able to understand clearly the audio and visual aids. If they are not clear, they only confuse. The two main types of  audio  equipment  systems  are  audio  tape  (cassettes and reel-to-reel) and compact disc systems. Records are nearing  obsolete  status. STAGING  A  PRESENTATION Learning Objective: Identify the methods of staging a speech   presentation. The use of audiovisual equipment and materials to support  a  speech  greatly  increases  our  ability  to communicate the Navy’s message. When audiovisual equipment  is  used  in  a  presentation,  however,  the speaking  situation  must  be  well-staged.  Giving  a  speech involves  more  than  well-organized  subject  matter, proper  equipment  and  complementary  audio  and  visual segments. Proper  staging  of  a  presentation  depends  on controlling the environment to the greatest possible extent, including the proper selection of the screen and establishing a clear line of vision for the audience. THE SCREEN The screen is often the weakest link in a projection chain. A projection screen interrupts the light falling on it from the projector (or other sources) and diverts it to the viewer’s eyes. The efficiency with which it does this affects  image  brightness,  evenness  of  image  brightness, color  saturation  and  contrast  of  image. The  screen  should  be  high  enough  so  that  the audience has an unobstructed view. From the persons in 6-24