174 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS oscillograph, where recordings were produced on strip-chart paper with curvilinear pens. Since the area under the curve has a direct relationship to frequency amplitude, chart curves were cut out with scissors and weighed on an analytical balance. Planimetering of the curves was found to be less accurate and, therefore, unsatisfactory. Integrator pre-amplifier calibration with a known input voltage makes possible comparisons between results taken at different times. Secondly, the comb pre-amplifier was connected to an oscilloscope (Fig. 4) to which outside electronic capacitors had been applied to POLYGRAPH METHOD TRANSISTOR I I INTEGRATING I I DRIVER I I I PRE-AMPLIFiERI [ II I [ I OSCILLOSCOPE Figure 3. Block diagram of polygraph method OSCILLOSCOPE METHOD mE-AMPLIFIERJ I I I I m I Figure 4. Block diagram of oscilloscope method slow the sweep. Deviations of the electron beam were recorded on positive film using a Polaroid©* camera. After film development, a photometer reading of transmitted light through the film gave results relative to deflection amplitude of the electron beam. For use, the transistorized pre-amplifier with the comb attached is held in the hand. A rigidly mounted tress or the subjeet's hair is combed with even strokes. Alternatively, tresses may be mounted on a constant speed rotating wheel and pulled through the rigidly mounted comb. Before the test combing is initiated, the comb is run through the hair several times to ensure no snarls and to establish timing. * Polaroid is a trade mark of Polaroid Corp., Cambridge, Mass.

DETERMINATION OF HAIR RASPINESS 175 At least ten comb strokes at one-second intervals comprise the test. Tests have been run on wet and dry preparations. All tresses weighed 2.0 (+0.1) g. Initially, damaged (bleached) and undamaged clean tresses were compared. In a second study, shampooed tresses were compared to tresses which had been shampooed and treated with a cationic rinse. Still further, in a third study, shampooed tresses were compared to tresses which had been treated with an experimental shampoo, which had been shown in previous subjective tests to increase hair managea- bility. A cross-over of the latter tress treatment supplemented this study. All results were analyzed by a Control Data © 160-A Computer,* using statistical FORTRANt programs written by one of the authors (W. C.W.). Outcoming data from the hair combing device fit a nor- mal distribution pattern. RESULTS Figure 5 gives representative recording examples. At the top left (A) is a compressed direct readout of three tress combings using the polygraph method. It is a series of positive and negative deflections and although not utilizable for quantitative interpretation, it is evidence of noise generation. However, pen response time prevents recording frequencies above 60 cyclesf sec. If the three previous signals are each electrically integrated, the record at the top right (B) is obtained. To increase sensitivity of the method, paper speed of the strip chart re- corder may be accelerated to give an expanded integrated readout, as seen in recording C. Records of control and treated tresses appear in the lower recordings of Fig. 5. Recording D is that of a clean, dry tress examined with the polygraph method (1 comb stroke). Record F is obtained from a sim- ilar tress examined by the oscilloscope method (4_ comb strokes). If a dry tress which has been treated with a cationic rinse after shampooing is combed at the same amplifier settings used with control tresses, it may be readily observed from records E and G that the signal drop from the controls (D and F) is considerable with both methods of recording. As seen in Table I (polygraph method), control tresses were compared to cationic rinse treated tresses, which when combed with the coarse * Control Data is a trade mark of Control Data Corp., Minneapolis, Minn. • FORTRAN is an abbreviation for FORmula TRANslation and was originally developed [or International Business Machine equipment.