Skip to main content
  • Utility Menu
  • Search
Harvard Logo
HARVARD.EDU

Collections Menu
  • Waywiser
  • People
  • Bibliography
  • Exhibitions
  • Thesaurus
  • My Object Lists
  • About
  • Sign in
Advanced Search
  • Home
  • Objects
  • phonograph speed indicator (two)
  • Images (2)

phonograph speed indicator (two)

  • Images (2)

phonograph speed indicator (two)

Date: 1900-1960
Inventory Number: 2004-1-0372
Classification: Phonograph
Subject:
communications, acoustics, metrology,
Maker: American
Cultural Region:
United States,
Dimensions:
each: 0.1 × 8.4 × 8.4 cm (1/16 × 3 5/16 × 3 5/16 in.)
Material:
cardboard,
Description:
Two cardboard disks, both with instructions for use on the underside. One disc has a plain circle in the center and black radial lines in the outer portion against a yellow-brown background. The other has black spiral lines radiating from the center against a yellow-brown background.
Signedon second disc: [...]CRAFT CORPO[...]
Inscribedon back of first disc (with truncated phrases marked by an ellipsis): INSTRUCTIONS / Place a record on the turntable in the us[...] / Place Stroboscope Disc on record (other si)[...] / Play record using grooves not covered by D[...] / If radial lines appear stationary (while Disc i[...] / [...]ng) turntable is totating at 78 revolutions per m[...] / [...]nstrument is, therefore properly regulated / If radial lines seem to be moving backw[...], turn regulating screw until they appear s[...] / Remove Stroboscope and file it away[...] / future use. / INstruments should be tested from t[...] / or five times a year). Records [...] per minute. Unless the [...]
on back of second disc: INDICATOR / Place Record on turn table. / Place this Spiral Speed Indicator on the / record, spiral side up. / Play record, using grooves not covered / by Indicator. / If black spiral lines do not appear to / stand still adjust Speed Regulator Knob / When lines appear to stand still record / is revolving a 78 revolutions per minute, / which is the speed at which records are / produced. It is very important to play re- / cords at this speed. / Note: When testing speed this indicat[...] / be lighted by a 60-cycle light.
FunctionUsed to calibrate record player speeds. When placed on top of a record and lit wih a stroboscope, the lines appar still at 78 RPM.
Curatorial RemarksThe inscriptions on the back were apparently written on a square board and then cut off when made into circles. Therefore, the full name of the constituent is not discernible.

78-RPM records were produced from 1898 to the late 1950s.
ProvenancePrivate Donor, Troy, NY.

Choose Collection

Create new collection

facebook iconTwitter Logo

_______________________________
Join Our Mailing List I Contact
_______________________________
The Collection of Historical Scientific Instruments
Science Center, Room 371 • 1 Oxford Street
Cambridge, MA 02138 •chsi@fas.harvard.edu
p. 617-495-2779 •
f. 617-496-5794
_______________________________
The CHSI is one of the

HMSC Logo

Exhibition Hours

The Putnam Gallery
(Science Center 136):
Monday through Friday, 11a.m. to 4p.m.


The Special Exhibitions Gallery
(Science Center 251):
Monday through Friday, 9a.m. to 5p.m.


The Foyer Gallery
Closed for Installation.

All galleries are closed on University Holidays.

Admission is free of charge.
Children must be escorted by an adult.

Admin Login
OpenScholar
Copyright © 2017 The President and Fellows of Harvard College | Privacy | Accessibility | Report Copyright Infringement

Choose Collection

Create new collection