A report of the computation of tables, to be used with the hydrometer recently adopted for use in the United States custom-houses / made under the superintendence of A.D. Bache, by R.S. McCulloh.

Alexander Dallas Bache

Date:: 1851

Credit: A report of the computation of tables, to be used with the hydrometer recently adopted for use in the United States custom-houses / made under the superintendence of A.D. Bache, by R.S. McCulloh. Source: Wellcome Collection.

Provider: This material has been provided by The Royal College of Surgeons of England. The original may be consulted at The Royal College of Surgeons of England.

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$r 21 [28] a standard Fahrenheit thermometer, made by J. G. Greiner, jr., in 1848, ,and a cylindrical glass jar for holding the liquid to be examined. Standard alcoholometer No. 2, belonging to the Treasury Department. This instrument is one of Greiner’s thermo-alcoholometers, certified by ;him to have been made with extreme care and accuracy. It differs from I the former in three respects: it is graduated to read half per cents.; enclosed 'witliin it is a Fahrenheit’s thermometer graduated from 5° to 115°; and tthe stem has not been ground to insure uniformity, but was made of a itube carefully selected and examined, so that any irregularities of its sec- itional area at different points may be too small to produce appreciable terrors. Accompanying this alcoholometer there is a separate Fahrenheit’s tthermometer, graduated upon milk-white glass, and packed in a neat imorocco case; also a large glass cylinder, with an attached brass holder [for the thermometer, designed for comparing ordinary instruments with ilhe standards. Standard thermometer No. 1, made in the year 1844 by J. G. Greiner, liunior, as recorded on its scale of white glass. This is the same instru- ment which was used in my experiments for determining the specific r^avities of alcoholic liquids, and which has already been described in 5 143, p. 516, Sen. Dec. No. 50, 1st sess. 30th Gongress. It is 'grad- lated, according to the centigrade scale, from — 20° to -j- 50°, and every degree is divided into five equal parts; each division is, therefore, equiva- lent to one-fifth of a degree, and temperatures may easily be read to the !3nth of a degree. No praise can be too great for the exquisite workman- feip of this most delicate and beautiful instrument. , Standard thermometer No. 2, made by Greiner in April, 1845, as stated ; fpon its scale. It is graduated on milk-white glass, from 0° to 240° r i'ahrenheit on one side, and into the corresponding centigrade degrees on 3j lie other. Both of the thermometers just described are packed in morocco cases; ■I nd it is stated of them by Greiner, that the uniformity of the bores of y.eir tubes v/as verified by the nicest means, and with the greatest care; >so, that the positions of their fixed points of graduation were determined ,.i dth accuracy. ,,, IRespectfully submitted by RICHARD S. McCULLOH. 'To Professor A. D. Bache, SuperiiUenderU of Weights, Measures, Balances, ^c. P .'r\ '.P$