312 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS TABLE II Drying Rates of Hair Sprays on Hair from the Aspect of Droplet Size and Distribution Experimental Treatment Cubic Inches Log•, cu in. At A• A• A• A• A• A,, A2 A2 Ao A2 B• G 3.44 X 10 -7 B• Cs 0.46 X 10-7 B• Ca 0.15 X 10-* B2 G 18.30 X 10 -7 B2 C• 6.81 ( 10-7 B= Ca 0.56 X 10-7 B• C• 385.00 X 10 -7 B• C2 333.00 X 10- B• C:• 337.00 X 10 -7 B• C• 394.00 X 10-7 B• Cs 670.00 X 10 -7 B• Ca 19.00 X 10-7 14.88 16.89 18.01 13.22 14.20 16.70 -- 10.17 -10.32 - 10.30 --10.15 --9.61 - 13.13 TABLE III Experimental Layout and Analysis of Variance Curl Length Before and Alter Spraying A i a Bi c A• B• A• B• A• A • B= a A• A• B2 A• B= 3 25 2 75 2 75 2 75 3 75 3.25 3.50 3.25 Source of Variance Degrees of Freedom Sum A.? B• 2.75 A2 B• 3.25 A• B• 2.75 A 2 B• 3.25 A • B• 4.50 A = B• 4.75 A• B2 4.50 A= B2 4.75 of Squares Mean Square Between A's 1 1.72 1.72 Between B's I 4.78 4.78 Interaction 1 1.14 1.14 Error 12 0.68 0.06 Total 15 8.32 MSA 1.72 Ft - - - 28.67 MSE 0.06 MSB 4.78 Fs - - - 79.67 MSE 0.06 MSI 1.14 _ MSE Fo.o:, = 4.75 F, ol = 9.33 0.06 - 19.00 "A• = Dry spray with small droplets. •' A2 = wet spray. * B• = Length of tress before spraying. a B2 = Length of tress after spraying.

THE ACTION OF HAIR SPRAYS ON HAIR 313 the hair, are small, even though there is some coalescence. Thus, a larger amount of surface area is exposed to the atmosphere, and drying takes place rapidly. Small droplets impinge upon hair fibers, and the effect on holding is statistical, i.e., droplets that do not land on fiber junctions are ineffective in holding except that they act as a reservoir for setting with a wet comb. With a spray of this type, soft holding and a fairly soft feel on hair can be expected. Figure 5. Brief spraying with dry spray (note partial wetting of hair shaft) Figure q. Long spraying with dry spray (note agglomeration to form large droplets) Figure 6 represents a case in which hair is sprayed for a long period of time with a dry spray. The same results occur when a wet spray is used for a short period of time. In this instance, the bombardment of hair with liquid droplets is so heavy that the droplets coalesce at a greater rate and run along the fiber until they reach hair junctions and, at this point, stop and dry. Heavy coalescence may take place when a dry spray is concentrated on one area for a relatively long time. Because of cooling, droplet evaporation is decreased. Droplets are cool when they strike the hair fiber because, during their flight from the can, the propellant is evaporating at a high rate, and the temperature of the droplets is decreasing proportionately. Figure 7 represents heavy spraying with a wet spray. Large droplets form, coalesce, and, because of their heavy concentration at the impact site, flow along the fiber and wet it. Droplets are so large that flow-out between adjacent or intersecting hair fibers will occur quite easily. Figure 8 represents typical junctions that are observed on hair sprayed with dry hair sprays. It can be seen that, with a dry spray or a light application of a wet spray, definite bonding or bridging tween adjacent or intersecting hair fibers occurs. There are many