Vibrators have come a long way since their modest beginnings only a short time ago. Manufacturers have developed them into effective, dependable tools with which contractors can both improve the quality of their work and increase their profits. This is a compelling combination well worth the consideration of all businessmen. However, to realize these advantages fullly, care must be exercised. Before vibrating, read the manufacturer's instruction manual. Also, check the number and condition of vibrators well in advance of placing concrete. Examine formwork before concreting commences. And unless your crew is exceptionally experienced in the proper use of vibrators, it will prove worthwhile to instruct them. Foremen should also check on the slump of all concrete being placed to assure that no water is being added by workmen to "make it more workable." Once concrete has been properly placed in well constructed forms, the next important step is correct use of the vibrator. When using an internal vibrator, the head should be inserted vertically in the concrete and then allowed to drop to an angle. For deep sections, the concrete should be vibrated in lifts. Two passes are sometimes needed so that low spots can be filled and compacted. After screeding has been completed, the concrete is finished and cured in the conventional manner.