APPARATUS FOR USE IN THE CONSTRUCTION INDUSTRY-NAMELY, LASER BEAM PROJECTORS, TARGETS UTILIZED WITH SAID PROJECTORS, SURVEYING TRANSITS, BLOWERS UTILIZED WITH SAID PROJECTORS, APPARATUS FOR CORRELATING THE ALIGNMENT OF SAID PROJECTORS WITH THE SIGHTING OF SAID TRANSITS, GRADE DETERMINING DEVICES, AND HARDWARE SPECIALLY DESIGNED FOR MOUNTING ALL OF THE ABOVE COMPONENTS IN A PREDETERMINED RELATIONSHIP TO EACH OTHER