cuthbertson_1932#
C. Cuthbertson and M. Cuthbertson, Proc. R. Soc. London A 135, 40 (1932)
Source record · Catalogue · Review register
Source kind: measurement
Recorded technique: Jamin interferometer with refractometer tubes 274.06 cm long, all-quartz optics, a quartz mercury-amalgam lamp; the interference pattern at each line was photographed before and after about 500-600 bands (at 5462.23 A) passed a crosswire while gas flowed in or out, and the fractional orders of the other lines fixed their band counts. The refractivity at the green mercury line was measured absolutely and the others from the band ratios, (mu_l - 1)/(mu_5462 - 1) = N_l l / (N_5462 5462) (p. 42). Neon: 2 litres from Keesom (Leiden), ‘very pure, freed from helium’; helium: British Oxygen Company ‘spectrally pure’, measured immediately after opening.
Materials in structured entries: He, Ne
Dataset quantities: refractivity
Contents: 4 datasets; 3 formulas.
Curation notes#
The paper states neither the temperature and pressure the refractivities refer to nor how they were reduced (Leonard 1974 attributes the spread of the older absolute values to ‘the different definitions adopted for a standard state and inadequate corrections for nonideality’). The authors compare them directly with their 1909-1910 values, which are for 0 degrees C and 760 mm, so the state is taken as 1 atm, 0 degrees C, with the density convention unknown (TC-9).
Wavelengths: neon’s are ‘those of Styles reduced to vacuum’ (Table II heading ‘in vacuo’, p. 44). Helium’s Table III prints them to ‘four figures’, truncated: the eleven lines it shares with Table II are corrected to Table II’s values by errata; 3126, 2926 and 2753 A stay truncated (up to 1 A short: about 2e-5 in n - 1 at 275 nm).
Formulas: mu - 1 = C / (n0^2 - n^2) with ‘n = V/lambda’, V the speed of light. The paper does not give V; V = 3e10 cm/s reproduces both calculated columns to within 0.14e-8, the rounding of the printed constants, and 2.99796e10 does worse (up to 0.25e-8), so 3e10 is implied.
Accuracy (p. 45): neon, ‘no discrepancy greater than 5 in the ninth decimal place’ between observation and formula, ‘and since the average number of bands read was about 600 and the bands were read to 1/20 we have no right to expect greater accuracy’. The absolute values at the green line: neon, four series 6725, 6727, 6725, 6725 e-8 (tbl_9c520fc15186, p. 43), with drift of 2-3 bands per hour the ‘principal source of error’ (‘much difficulty was experienced in carrying the accuracy beyond the third significant figure’ before drift corrections); helium, three pairs of measurements 3489, 3485, 3492 e-8, mean 3489 (p. 45; the library’s Markdown drops the 3485, checked on the page image). The per-point uncertainties below are the rms of the paper’s obs - calc columns; the systematic ones the spread of the absolute values (neon 2 in 6725, helium the standard deviation 3.5 in 3489).
Also in the paper, reproduced: Koch’s (1913) helium formula (recorded as a formula below), the 1909 and 1910 neon formulas (cuthbertson_1910b, cuthbertson_1910) and Table I, the 1910 constants of all five gases, which are half the 1910 paper’s (whose formulas are for 2(mu - 1); recorded with cuthbertson_1910). Table IV repeats the 1910 constants for Ar, Kr and Xe beside the new He and Ne ones.
Recorded bibliographic identity status: VALIDATED_WITH_WARNINGS. This concerns identification of the source; it does not establish the scientific correctness of its contents.
Datasets#
cuthbertson_1932/experiment_Ne#
{
"id": "experiment_Ne",
"material": "Ne",
"file": "Ne/cuthbertson_1932__experiment_Ne.csv",
"table": "tbl_4ee024d8daf8",
"quantity": "refractivity",
"scale": 1e-08,
"abscissa_unit": "angstrom",
"wavelength_medium": "vacuum",
"state": "1atm_0C",
"density": "unknown",
"use": "primary",
"uncertainty": {
"absolute": 0.29,
"level": "rms",
"systematic_relative": 0.0003
}
}
Table II, observed column. The state is assumed (see the source notes).
cuthbertson_1932/fit_Ne#
{
"id": "fit_Ne",
"material": "Ne",
"file": "Ne/cuthbertson_1932__fit_Ne.csv",
"table": "tbl_4ee024d8daf8",
"quantity": "refractivity",
"scale": 1e-08,
"abscissa_unit": "angstrom",
"wavelength_medium": "vacuum",
"state": "1atm_0C",
"density": "unknown",
"use": "check"
}
Table II, calculated column: the paper’s one-term formula (formula ne_1932).
cuthbertson_1932/experiment_He#
{
"id": "experiment_He",
"material": "He",
"file": "He/cuthbertson_1932__experiment_He.csv",
"table": "tbl_01cd89e4e3aa",
"quantity": "refractivity",
"scale": 1e-08,
"abscissa_unit": "angstrom",
"wavelength_medium": "vacuum",
"state": "1atm_0C",
"density": "unknown",
"use": "primary",
"uncertainty": {
"absolute": 0.15,
"level": "rms",
"systematic_relative": 0.001
}
}
Table III, observed column; wavelengths corrected from four figures where Table II gives them. The 5462 A value (3489.0) is quoted by Mansfield and Peck (1969, Table III). The state is assumed (see the source notes).
cuthbertson_1932/fit_He#
{
"id": "fit_He",
"material": "He",
"file": "He/cuthbertson_1932__fit_He.csv",
"table": "tbl_01cd89e4e3aa",
"quantity": "refractivity",
"scale": 1e-08,
"abscissa_unit": "angstrom",
"wavelength_medium": "vacuum",
"state": "1atm_0C",
"density": "unknown",
"use": "check"
}
Table III, calculated column: the paper’s one-term formula (formula he_1932).
Formulas#
cuthbertson_1932/ne_1932#
{
"id": "ne_1932",
"material": "Ne",
"equation": "unnumbered, p. 45; Table IV, p. 47",
"printed": "mu - 1 = 2.61303 x 10^27 / (39160 x 10^27 - n^2)",
"variable": "n = V/lambda: frequency in s^-1, lambda the vacuum wavelength in cm, V = 3e10 cm/s (implied, see notes)",
"state": "1atm_0C",
"density": "unknown",
"range": "289.4-546.2 nm (Table II)",
"coefficients": {
"C": "2.61303e27",
"n0_squared": "39160e27"
},
"check": "With V = 3e10 cm/s it reproduces Table II's calculated column to within 0.14e-8 (the rounding of the constants). Checked 2026-09-24."
}
Least-squares fit to Table II and the absolute green-line value (p. 45); free wavelength V/n0 = 479.4 A.
cuthbertson_1932/he_1932#
{
"id": "he_1932",
"material": "He",
"equation": "unnumbered, p. 45; Table IV, p. 47",
"printed": "mu - 1 = 1.32614 x 10^27 / (38313.7 x 10^27 - n^2)",
"variable": "n = V/lambda: frequency in s^-1, lambda the vacuum wavelength in cm, V = 3e10 cm/s (implied, see notes)",
"state": "1atm_0C",
"density": "unknown",
"range": "275.3-546.2 nm (Table III)",
"coefficients": {
"C": "1.32614e27",
"n0_squared": "38313.7e27"
},
"check": "With V = 3e10 cm/s it reproduces Table III's calculated column to within 0.1e-8; lambda0 = V/n0 = 484.67 A, the paper's 'our determination leads to 484.67 A.U.' (p. 46). Checked 2026-09-24."
}
cuthbertson_1932/koch_1913_he#
{
"id": "koch_1913_he",
"material": "He",
"equation": "unnumbered, p. 46 (Koch 1913, reproduced)",
"printed": "(2/3)(mu^2 + 2)/(mu^2 - 1) = 28860.8 - 67.763 x 10^-8 / lambda^2 (lambda in centimetres); Sellmeier form mu - 1 = 1.32816 x 10^27 / (38331.7 x 10^27 - n^2)",
"variable": "lambda: wavelength in cm (medium not stated); n = V/lambda",
"state": "1atm_0C",
"density": "unknown",
"range": "230.3-546.2 nm ('over the range 5462-2303')",
"coefficients": {
"A": "28860.8",
"B": "67.763e-8",
"C": "1.32816e27",
"n0_squared": "38331.7e27"
},
"check": "The first form gives 3.4924e-5 at 5462 A (Koch's green-line value, quoted p. 45: 0.000034925); its Sellmeier equivalent follows with V = 3e10 cm/s (C = V^2/B = 1.32816e27, n0^2 = A C = 38331.7e27). Checked 2026-09-24."
}
Reproduced from J. Koch, Ark. Mat. Astr. Fys. 9, No. 6 (1913), not in the library; the paper says Koch counted only 53 bands. Koch’s free wavelength 484.55 A.
Corrections#
[
{
"dataset": "experiment_He",
"row": "5462",
"column": "x",
"printed": "5462",
"corrected": "5462.23",
"reason": "Table III prints the wavelengths truncated to 'four figures'; this mercury line is printed in full, in vacuo, in Table II (neon), measured with the same lamp and interferometer.",
"evidence": "Table II (tbl_4ee024d8daf8.jpg) lists 5462.23; every four-figure helium wavelength shared with it is its truncation, not its rounding (4078.97 -> 4078, 3132.59 -> 3132). The one-term He formula reproduces the calculated column to within 0.1e-8 with either the truncated or the full wavelengths (checked 2026-09-24), so the column does not show which the authors used."
},
{
"dataset": "experiment_He",
"row": "4359",
"column": "x",
"printed": "4359",
"corrected": "4359.54",
"reason": "Table III prints the wavelengths truncated to 'four figures'; this mercury line is printed in full, in vacuo, in Table II (neon), measured with the same lamp and interferometer.",
"evidence": "Table II (tbl_4ee024d8daf8.jpg) lists 4359.54; every four-figure helium wavelength shared with it is its truncation, not its rounding (4078.97 -> 4078, 3132.59 -> 3132). The one-term He formula reproduces the calculated column to within 0.1e-8 with either the truncated or the full wavelengths (checked 2026-09-24), so the column does not show which the authors used."
},
{
"dataset": "experiment_He",
"row": "4078",
"column": "x",
"printed": "4078",
"corrected": "4078.97",
"reason": "Table III prints the wavelengths truncated to 'four figures'; this mercury line is printed in full, in vacuo, in Table II (neon), measured with the same lamp and interferometer.",
"evidence": "Table II (tbl_4ee024d8daf8.jpg) lists 4078.97; every four-figure helium wavelength shared with it is its truncation, not its rounding (4078.97 -> 4078, 3132.59 -> 3132). The one-term He formula reproduces the calculated column to within 0.1e-8 with either the truncated or the full wavelengths (checked 2026-09-24), so the column does not show which the authors used."
},
{
"dataset": "experiment_He",
"row": "4047",
"column": "x",
"printed": "4047",
"corrected": "4047.68",
"reason": "Table III prints the wavelengths truncated to 'four figures'; this mercury line is printed in full, in vacuo, in Table II (neon), measured with the same lamp and interferometer.",
"evidence": "Table II (tbl_4ee024d8daf8.jpg) lists 4047.68; every four-figure helium wavelength shared with it is its truncation, not its rounding (4078.97 -> 4078, 3132.59 -> 3132). The one-term He formula reproduces the calculated column to within 0.1e-8 with either the truncated or the full wavelengths (checked 2026-09-24), so the column does not show which the authors used."
},
{
"dataset": "experiment_He",
"row": "3907",
"column": "x",
"printed": "3907",
"corrected": "3907.56",
"reason": "Table III prints the wavelengths truncated to 'four figures'; this mercury line is printed in full, in vacuo, in Table II (neon), measured with the same lamp and interferometer.",
"evidence": "Table II (tbl_4ee024d8daf8.jpg) lists 3907.56; every four-figure helium wavelength shared with it is its truncation, not its rounding (4078.97 -> 4078, 3132.59 -> 3132). The one-term He formula reproduces the calculated column to within 0.1e-8 with either the truncated or the full wavelengths (checked 2026-09-24), so the column does not show which the authors used."
},
{
"dataset": "experiment_He",
"row": "3664",
"column": "x",
"printed": "3664",
"corrected": "3664.10",
"reason": "Table III prints the wavelengths truncated to 'four figures'; this mercury line is printed in full, in vacuo, in Table II (neon), measured with the same lamp and interferometer.",
"evidence": "Table II (tbl_4ee024d8daf8.jpg) lists 3664.10; every four-figure helium wavelength shared with it is its truncation, not its rounding (4078.97 -> 4078, 3132.59 -> 3132). The one-term He formula reproduces the calculated column to within 0.1e-8 with either the truncated or the full wavelengths (checked 2026-09-24), so the column does not show which the authors used."
},
{
"dataset": "experiment_He",
"row": "3342",
"column": "x",
"printed": "3342",
"corrected": "3342.42",
"reason": "Table III prints the wavelengths truncated to 'four figures'; this mercury line is printed in full, in vacuo, in Table II (neon), measured with the same lamp and interferometer.",
"evidence": "Table II (tbl_4ee024d8daf8.jpg) lists 3342.42; every four-figure helium wavelength shared with it is its truncation, not its rounding (4078.97 -> 4078, 3132.59 -> 3132). The one-term He formula reproduces the calculated column to within 0.1e-8 with either the truncated or the full wavelengths (checked 2026-09-24), so the column does not show which the authors used."
},
{
"dataset": "experiment_He",
"row": "3132",
"column": "x",
"printed": "3132",
"corrected": "3132.59",
"reason": "Table III prints the wavelengths truncated to 'four figures'; this mercury line is printed in full, in vacuo, in Table II (neon), measured with the same lamp and interferometer.",
"evidence": "Table II (tbl_4ee024d8daf8.jpg) lists 3132.59; every four-figure helium wavelength shared with it is its truncation, not its rounding (4078.97 -> 4078, 3132.59 -> 3132). The one-term He formula reproduces the calculated column to within 0.1e-8 with either the truncated or the full wavelengths (checked 2026-09-24), so the column does not show which the authors used."
},
{
"dataset": "experiment_He",
"row": "3022",
"column": "x",
"printed": "3022",
"corrected": "3022.37",
"reason": "Table III prints the wavelengths truncated to 'four figures'; this mercury line is printed in full, in vacuo, in Table II (neon), measured with the same lamp and interferometer.",
"evidence": "Table II (tbl_4ee024d8daf8.jpg) lists 3022.37; every four-figure helium wavelength shared with it is its truncation, not its rounding (4078.97 -> 4078, 3132.59 -> 3132). The one-term He formula reproduces the calculated column to within 0.1e-8 with either the truncated or the full wavelengths (checked 2026-09-24), so the column does not show which the authors used."
},
{
"dataset": "experiment_He",
"row": "2968",
"column": "x",
"printed": "2968",
"corrected": "2968.13",
"reason": "Table III prints the wavelengths truncated to 'four figures'; this mercury line is printed in full, in vacuo, in Table II (neon), measured with the same lamp and interferometer.",
"evidence": "Table II (tbl_4ee024d8daf8.jpg) lists 2968.13; every four-figure helium wavelength shared with it is its truncation, not its rounding (4078.97 -> 4078, 3132.59 -> 3132). The one-term He formula reproduces the calculated column to within 0.1e-8 with either the truncated or the full wavelengths (checked 2026-09-24), so the column does not show which the authors used."
},
{
"dataset": "experiment_He",
"row": "2894",
"column": "x",
"printed": "2894",
"corrected": "2894.44",
"reason": "Table III prints the wavelengths truncated to 'four figures'; this mercury line is printed in full, in vacuo, in Table II (neon), measured with the same lamp and interferometer.",
"evidence": "Table II (tbl_4ee024d8daf8.jpg) lists 2894.44; every four-figure helium wavelength shared with it is its truncation, not its rounding (4078.97 -> 4078, 3132.59 -> 3132). The one-term He formula reproduces the calculated column to within 0.1e-8 with either the truncated or the full wavelengths (checked 2026-09-24), so the column does not show which the authors used."
},
{
"dataset": "fit_He",
"row": "5462",
"column": "x",
"printed": "5462",
"corrected": "5462.23",
"reason": "Table III prints the wavelengths truncated to 'four figures'; this mercury line is printed in full, in vacuo, in Table II (neon), measured with the same lamp and interferometer.",
"evidence": "Table II (tbl_4ee024d8daf8.jpg) lists 5462.23; every four-figure helium wavelength shared with it is its truncation, not its rounding (4078.97 -> 4078, 3132.59 -> 3132). The one-term He formula reproduces the calculated column to within 0.1e-8 with either the truncated or the full wavelengths (checked 2026-09-24), so the column does not show which the authors used."
},
{
"dataset": "fit_He",
"row": "4359",
"column": "x",
"printed": "4359",
"corrected": "4359.54",
"reason": "Table III prints the wavelengths truncated to 'four figures'; this mercury line is printed in full, in vacuo, in Table II (neon), measured with the same lamp and interferometer.",
"evidence": "Table II (tbl_4ee024d8daf8.jpg) lists 4359.54; every four-figure helium wavelength shared with it is its truncation, not its rounding (4078.97 -> 4078, 3132.59 -> 3132). The one-term He formula reproduces the calculated column to within 0.1e-8 with either the truncated or the full wavelengths (checked 2026-09-24), so the column does not show which the authors used."
},
{
"dataset": "fit_He",
"row": "4078",
"column": "x",
"printed": "4078",
"corrected": "4078.97",
"reason": "Table III prints the wavelengths truncated to 'four figures'; this mercury line is printed in full, in vacuo, in Table II (neon), measured with the same lamp and interferometer.",
"evidence": "Table II (tbl_4ee024d8daf8.jpg) lists 4078.97; every four-figure helium wavelength shared with it is its truncation, not its rounding (4078.97 -> 4078, 3132.59 -> 3132). The one-term He formula reproduces the calculated column to within 0.1e-8 with either the truncated or the full wavelengths (checked 2026-09-24), so the column does not show which the authors used."
},
{
"dataset": "fit_He",
"row": "4047",
"column": "x",
"printed": "4047",
"corrected": "4047.68",
"reason": "Table III prints the wavelengths truncated to 'four figures'; this mercury line is printed in full, in vacuo, in Table II (neon), measured with the same lamp and interferometer.",
"evidence": "Table II (tbl_4ee024d8daf8.jpg) lists 4047.68; every four-figure helium wavelength shared with it is its truncation, not its rounding (4078.97 -> 4078, 3132.59 -> 3132). The one-term He formula reproduces the calculated column to within 0.1e-8 with either the truncated or the full wavelengths (checked 2026-09-24), so the column does not show which the authors used."
},
{
"dataset": "fit_He",
"row": "3907",
"column": "x",
"printed": "3907",
"corrected": "3907.56",
"reason": "Table III prints the wavelengths truncated to 'four figures'; this mercury line is printed in full, in vacuo, in Table II (neon), measured with the same lamp and interferometer.",
"evidence": "Table II (tbl_4ee024d8daf8.jpg) lists 3907.56; every four-figure helium wavelength shared with it is its truncation, not its rounding (4078.97 -> 4078, 3132.59 -> 3132). The one-term He formula reproduces the calculated column to within 0.1e-8 with either the truncated or the full wavelengths (checked 2026-09-24), so the column does not show which the authors used."
},
{
"dataset": "fit_He",
"row": "3664",
"column": "x",
"printed": "3664",
"corrected": "3664.10",
"reason": "Table III prints the wavelengths truncated to 'four figures'; this mercury line is printed in full, in vacuo, in Table II (neon), measured with the same lamp and interferometer.",
"evidence": "Table II (tbl_4ee024d8daf8.jpg) lists 3664.10; every four-figure helium wavelength shared with it is its truncation, not its rounding (4078.97 -> 4078, 3132.59 -> 3132). The one-term He formula reproduces the calculated column to within 0.1e-8 with either the truncated or the full wavelengths (checked 2026-09-24), so the column does not show which the authors used."
},
{
"dataset": "fit_He",
"row": "3342",
"column": "x",
"printed": "3342",
"corrected": "3342.42",
"reason": "Table III prints the wavelengths truncated to 'four figures'; this mercury line is printed in full, in vacuo, in Table II (neon), measured with the same lamp and interferometer.",
"evidence": "Table II (tbl_4ee024d8daf8.jpg) lists 3342.42; every four-figure helium wavelength shared with it is its truncation, not its rounding (4078.97 -> 4078, 3132.59 -> 3132). The one-term He formula reproduces the calculated column to within 0.1e-8 with either the truncated or the full wavelengths (checked 2026-09-24), so the column does not show which the authors used."
},
{
"dataset": "fit_He",
"row": "3132",
"column": "x",
"printed": "3132",
"corrected": "3132.59",
"reason": "Table III prints the wavelengths truncated to 'four figures'; this mercury line is printed in full, in vacuo, in Table II (neon), measured with the same lamp and interferometer.",
"evidence": "Table II (tbl_4ee024d8daf8.jpg) lists 3132.59; every four-figure helium wavelength shared with it is its truncation, not its rounding (4078.97 -> 4078, 3132.59 -> 3132). The one-term He formula reproduces the calculated column to within 0.1e-8 with either the truncated or the full wavelengths (checked 2026-09-24), so the column does not show which the authors used."
},
{
"dataset": "fit_He",
"row": "3022",
"column": "x",
"printed": "3022",
"corrected": "3022.37",
"reason": "Table III prints the wavelengths truncated to 'four figures'; this mercury line is printed in full, in vacuo, in Table II (neon), measured with the same lamp and interferometer.",
"evidence": "Table II (tbl_4ee024d8daf8.jpg) lists 3022.37; every four-figure helium wavelength shared with it is its truncation, not its rounding (4078.97 -> 4078, 3132.59 -> 3132). The one-term He formula reproduces the calculated column to within 0.1e-8 with either the truncated or the full wavelengths (checked 2026-09-24), so the column does not show which the authors used."
},
{
"dataset": "fit_He",
"row": "2968",
"column": "x",
"printed": "2968",
"corrected": "2968.13",
"reason": "Table III prints the wavelengths truncated to 'four figures'; this mercury line is printed in full, in vacuo, in Table II (neon), measured with the same lamp and interferometer.",
"evidence": "Table II (tbl_4ee024d8daf8.jpg) lists 2968.13; every four-figure helium wavelength shared with it is its truncation, not its rounding (4078.97 -> 4078, 3132.59 -> 3132). The one-term He formula reproduces the calculated column to within 0.1e-8 with either the truncated or the full wavelengths (checked 2026-09-24), so the column does not show which the authors used."
},
{
"dataset": "fit_He",
"row": "2894",
"column": "x",
"printed": "2894",
"corrected": "2894.44",
"reason": "Table III prints the wavelengths truncated to 'four figures'; this mercury line is printed in full, in vacuo, in Table II (neon), measured with the same lamp and interferometer.",
"evidence": "Table II (tbl_4ee024d8daf8.jpg) lists 2894.44; every four-figure helium wavelength shared with it is its truncation, not its rounding (4078.97 -> 4078, 3132.59 -> 3132). The one-term He formula reproduces the calculated column to within 0.1e-8 with either the truncated or the full wavelengths (checked 2026-09-24), so the column does not show which the authors used."
}
]
Formula corrections, where recorded, appear with their formulas above. Curation notes may also discuss corrections or unresolved interpretation. Consult the review register for the checks and decisions.