214 



ANNUAL EEPORT SMITHSONIAN INSTITUTION, 1908. 



Fig. 5. — Berliner reproducing apparatus 

 (1888). (Cut furnished by E. Berliner.) 



conditions of the diaphragm, which conditions necessarily vary from time to 

 time, and constitute some of the causes of imperfect reproduction of recorded 

 sounds. 



It is this feature of the positive control of the diaphragm, coupled 

 with the uniform friction and resistance in the cutting operation, and 

 the consequent accurate tracing of the curve of the sound wave, that 

 has brought the Berliner type of machine to the forefront as a musical 



instrument. IVliile the cylinder 

 machine with the up and down 

 cut offers advantages for making 

 records at home and for office 

 work, being handier, for instance, 

 than the disk recording machine, 

 it has not been found possible to 

 obtain the same truth of repro- 

 duction of musical sounds that 

 can be obtained with the gramo- 

 phone. An examination of the 

 microscopic undulations in the 

 sound wave, v^diich determine 

 its pitch, loudness, and quality of timbre (some examples of which 

 I shall show you presently), will make this easy to understand. 



In the second or improved form of gramophone described in Ber- 

 liner's patent, a flat disk record is used, which, he says, offers advan- 

 tages for copying purposes. Here a disk of glass is employed, and 

 this is covered preferably with a semifluid coating of ink or paint, in 

 which the stylus traces or cuts an undulating line as before. This 

 coating he prefers, because it does not flake and leave a rough-edged 

 line, like the lampblack record. A turntable carries 

 the record disk, and is rotated by any suitable means. 

 As it revolves it is caused to travel slowly sideways 

 past the recording point, so that the sound line takes 

 the form of a sinuous spiral running from the outer 

 edge of the record toward the center, or vice versa. 

 A permanent record in metal is obtained by photo- 

 engraving. 



Mr. Berliner's next step was to make a disk record 

 in solid material by direct etching. (United States patent 382790.) 

 To this end he coated a disk or cylinder of zinc or glass with a layer 

 of some substance which, while offering no perceptible mechanical re- 

 sistance to the movements of the recording stylus, resisted the chemical 

 action of acids. The coating he preferred consisted of beeswax dis- 

 solved in benzine. A^^ien the recording stylus had traced out its line 

 on the record, and exposed the solid disk below, the latter was etched. 



Fig. 6. — R e c o r d 

 lines a888). X 

 6. (Cut fur- 

 nished by E. 

 Berliner. 



