Abstract

The photoelectric photodensitometer described was developed for determining fine structure from “match-point” spectrum photographs. It consists of a push-pull photo-cell circuit, transformer coupled to an amplifier and cathode-ray oscillograph, and two optical systems with a.c. operated light sources for projecting the spectra onto the photo-cell slit and for forming an image of the wave-length scale which indicates the region of the spectrum being matched. As the projected spectra are moved horizontally across the slit, a change in phase occurs in the a.c. output of the photo-cell circuit on passing through a match point. The corresponding change in oscillograph pattern indicates whether the absorption is increasing or decreasing, and permits true match points to be distinguished from decreases in intensity due to dense spectrum lines in matching line spectra.

© 1939 Optical Society of America

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  1. F. F. Heyroth and J. R. Loofbourow, J. Am. Chem. Soc. 52, 3441 (1931).
    [CrossRef]
  2. J. R. Loofbourow, Bull. Basic Sci. Research 5, 46 (1933).
  3. Lavin, Northrup, and Taylor, J. Am. Chem. Soc. 55, 3497 (1933); Ross, J. Biol. Chem. 104, 531 (1934); Lavin and Northrup, J. Am. Chem. Soc. 57, 874 (1935); Feraud, Dunn, and Kaplan, J. Biol. Chem. 112, 323 (1935); Coulter, Stone, and Kabot, J. Gen. Physiol. 19, 739 (1936);Holiday J. Sci. Inst. 14, 166 (1937); Holiday, Biochem. J. 31, 1299 (1937); Lavin and Stanley, J. Biol. Chem. 118, 269 (1937).
    [CrossRef]
  4. H. Kronenberger, Zeits. f. Physik 63, 494 (1930).
    [CrossRef]
  5. J. B. Conant and F. H. Crawford, Proc. Nat. Acad. Sci. 16, 552 (1930).
    [CrossRef]
  6. L. B. Arnold and G. B. Kistiakowsky, J. Am. Chem. Soc. 54, 1713 (1932).
    [CrossRef]
  7. J. R. Loofbourow, Studies Inst. Divi Thomae, in publication.
  8. This transformer, which is of the type used in motion picture push-pull soundheads, was kindly loaned by Mr. M. G. Thomas of the Altec Corporation.
  9. See G. R. Harrison, J. Opt. Soc. Am. 24, 59 (1934) for a review of such devices.
    [CrossRef]

1934 (1)

1933 (2)

J. R. Loofbourow, Bull. Basic Sci. Research 5, 46 (1933).

Lavin, Northrup, and Taylor, J. Am. Chem. Soc. 55, 3497 (1933); Ross, J. Biol. Chem. 104, 531 (1934); Lavin and Northrup, J. Am. Chem. Soc. 57, 874 (1935); Feraud, Dunn, and Kaplan, J. Biol. Chem. 112, 323 (1935); Coulter, Stone, and Kabot, J. Gen. Physiol. 19, 739 (1936);Holiday J. Sci. Inst. 14, 166 (1937); Holiday, Biochem. J. 31, 1299 (1937); Lavin and Stanley, J. Biol. Chem. 118, 269 (1937).
[CrossRef]

1932 (1)

L. B. Arnold and G. B. Kistiakowsky, J. Am. Chem. Soc. 54, 1713 (1932).
[CrossRef]

1931 (1)

F. F. Heyroth and J. R. Loofbourow, J. Am. Chem. Soc. 52, 3441 (1931).
[CrossRef]

1930 (2)

H. Kronenberger, Zeits. f. Physik 63, 494 (1930).
[CrossRef]

J. B. Conant and F. H. Crawford, Proc. Nat. Acad. Sci. 16, 552 (1930).
[CrossRef]

Arnold, L. B.

L. B. Arnold and G. B. Kistiakowsky, J. Am. Chem. Soc. 54, 1713 (1932).
[CrossRef]

Conant, J. B.

J. B. Conant and F. H. Crawford, Proc. Nat. Acad. Sci. 16, 552 (1930).
[CrossRef]

Crawford, F. H.

J. B. Conant and F. H. Crawford, Proc. Nat. Acad. Sci. 16, 552 (1930).
[CrossRef]

Harrison, G. R.

Heyroth, F. F.

F. F. Heyroth and J. R. Loofbourow, J. Am. Chem. Soc. 52, 3441 (1931).
[CrossRef]

Kistiakowsky, G. B.

L. B. Arnold and G. B. Kistiakowsky, J. Am. Chem. Soc. 54, 1713 (1932).
[CrossRef]

Kronenberger, H.

H. Kronenberger, Zeits. f. Physik 63, 494 (1930).
[CrossRef]

Lavin,

Lavin, Northrup, and Taylor, J. Am. Chem. Soc. 55, 3497 (1933); Ross, J. Biol. Chem. 104, 531 (1934); Lavin and Northrup, J. Am. Chem. Soc. 57, 874 (1935); Feraud, Dunn, and Kaplan, J. Biol. Chem. 112, 323 (1935); Coulter, Stone, and Kabot, J. Gen. Physiol. 19, 739 (1936);Holiday J. Sci. Inst. 14, 166 (1937); Holiday, Biochem. J. 31, 1299 (1937); Lavin and Stanley, J. Biol. Chem. 118, 269 (1937).
[CrossRef]

Loofbourow, J. R.

J. R. Loofbourow, Bull. Basic Sci. Research 5, 46 (1933).

F. F. Heyroth and J. R. Loofbourow, J. Am. Chem. Soc. 52, 3441 (1931).
[CrossRef]

J. R. Loofbourow, Studies Inst. Divi Thomae, in publication.

Northrup,

Lavin, Northrup, and Taylor, J. Am. Chem. Soc. 55, 3497 (1933); Ross, J. Biol. Chem. 104, 531 (1934); Lavin and Northrup, J. Am. Chem. Soc. 57, 874 (1935); Feraud, Dunn, and Kaplan, J. Biol. Chem. 112, 323 (1935); Coulter, Stone, and Kabot, J. Gen. Physiol. 19, 739 (1936);Holiday J. Sci. Inst. 14, 166 (1937); Holiday, Biochem. J. 31, 1299 (1937); Lavin and Stanley, J. Biol. Chem. 118, 269 (1937).
[CrossRef]

Taylor,

Lavin, Northrup, and Taylor, J. Am. Chem. Soc. 55, 3497 (1933); Ross, J. Biol. Chem. 104, 531 (1934); Lavin and Northrup, J. Am. Chem. Soc. 57, 874 (1935); Feraud, Dunn, and Kaplan, J. Biol. Chem. 112, 323 (1935); Coulter, Stone, and Kabot, J. Gen. Physiol. 19, 739 (1936);Holiday J. Sci. Inst. 14, 166 (1937); Holiday, Biochem. J. 31, 1299 (1937); Lavin and Stanley, J. Biol. Chem. 118, 269 (1937).
[CrossRef]

Bull. Basic Sci. Research (1)

J. R. Loofbourow, Bull. Basic Sci. Research 5, 46 (1933).

J. Am. Chem. Soc. (3)

Lavin, Northrup, and Taylor, J. Am. Chem. Soc. 55, 3497 (1933); Ross, J. Biol. Chem. 104, 531 (1934); Lavin and Northrup, J. Am. Chem. Soc. 57, 874 (1935); Feraud, Dunn, and Kaplan, J. Biol. Chem. 112, 323 (1935); Coulter, Stone, and Kabot, J. Gen. Physiol. 19, 739 (1936);Holiday J. Sci. Inst. 14, 166 (1937); Holiday, Biochem. J. 31, 1299 (1937); Lavin and Stanley, J. Biol. Chem. 118, 269 (1937).
[CrossRef]

F. F. Heyroth and J. R. Loofbourow, J. Am. Chem. Soc. 52, 3441 (1931).
[CrossRef]

L. B. Arnold and G. B. Kistiakowsky, J. Am. Chem. Soc. 54, 1713 (1932).
[CrossRef]

J. Opt. Soc. Am. (1)

Proc. Nat. Acad. Sci. (1)

J. B. Conant and F. H. Crawford, Proc. Nat. Acad. Sci. 16, 552 (1930).
[CrossRef]

Zeits. f. Physik (1)

H. Kronenberger, Zeits. f. Physik 63, 494 (1930).
[CrossRef]

Other (2)

J. R. Loofbourow, Studies Inst. Divi Thomae, in publication.

This transformer, which is of the type used in motion picture push-pull soundheads, was kindly loaned by Mr. M. G. Thomas of the Altec Corporation.

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Figures (2)

Fig. 1
Fig. 1

Schematic diagram of push-pull photoelectric photodensitometer (power supply circuits omitted).

Fig. 2
Fig. 2

Example of absorption spectrum showing increased resolution obtained with push-pull photoelectric matching device as compared with visual matchings.

Tables (1)

Tables Icon

Table I Example showing range of values obtained in repeated trials with photoelectric method for matching spectra. Material, uracil.