Page:EB1911 - Volume 14.djvu/177

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165
HYDROPATHY


to 100 principal divisions. In the centre of each weight is a hole capable of admitting the lowest and thickest end of the conical stem C, and a slot is cut into it just wide enough to allow the upper part of the cone to pass. Each weight can thus be dropped on to the lower stem so as to rest on the counterpoise B. The weights are marked 10, 20, ... 90; and in using the instrument that weight must be selected which will allow it to float in the liquid with a portion only of the stem submerged. Then the reading of the scale at the line of flotation, added to the number on the weight, gives the reading required. A small supernumerary weight F is added, which can be placed upon the top of the stem. F is so adjusted that when the 60 weight is placed on the lower stem the instrument sinks to the same point in distilled water when F is attached as in proof spirit when F is removed. The best instruments are now constructed for revenue purposes of silver, heavily gilded, because it was found that saccharic acid contained in some spirits attacked brass behind the gilding.

The following table gives the specific gravities corresponding to the principal graduations on Sikes’s hydrometer at 60° F. and 62° F., together with the corresponding strengths of spirits. The latter are based upon the tables of Charles Gilpin, clerk to the Royal Society, for which the reader is referred to the Phil. Trans. for 1794. Gilpin’s work is a model for its accuracy and thoroughness of detail, and his results have scarcely been improved upon by more recent workers. The merit of Sikes’s system lies not so much in the hydrometer as in the complete system of tables by which the readings of the instrument are at once converted into percentage of proof-spirit.

Table showing the Densities corresponding to the Indications of
Sike’s Hydrometer.
Sike’s
Indications.
60° F. 62° F.
Density. Proof
Spirit
per
cent.
Density. Proof
Spirit
per
cent.
 0 .815297 167.0 .815400 166.5
 1 .816956 166.1 .817059 165.6
 2 .818621 165.3 .818725 164.8
 3 .820294 164.5 .820397 163.9
 4 .821973 163.6 .822077 163.1
 5 .823659 162.7 .823763 162.3
 6 .825352 161.8 .825457 161.4
 7 .827052 160.9 .827157 160.5
 8 .828759 160.0 .828864 159.6
 9 .830473 159.1 .830578 158.7
10 .832195 158.2 .832300 157.8
11 .833888 157.3 .833993 156.8
12 .835587 156.4 .835692 155.9
13 .837294 155.5 .837400 155.0
14 .839008 154.6 .839114 154.0
15 .840729 153.7 .840835 153.1
16 .842458 152.7 .842564 152.1
17 .844193 151.7 .844299 151.1
18 .845936 150.7 .846042 150.1
19 .847685 149.7 .847792 149.1
20 .849442 148.7 .849549 148.1
20B .849393 148.7 .849500 148.1
21 .851122 147.6 .851229 147.1
22 .852857 146.6 .852964 146.1
23 .854599 145.6 .854707 145.1
24 .856348 144.6 .856456 144.0
25 .858105 143.5 .858213 142.9
26 .859869 142.4 .859978 141.8
27 .861640 141.3 .861749 140.8
28 .863419 140.2 .863528 139.7
29 .865204 139.1 .865313 138.5
30 .866998 138.0 .867107 137.4
30B .866991 138.0 .867100 137.4
31 .868755 136.9 .868865 136.2
32 .870526 135.7 .870636 135.1
33 .872305 134.5 .872415 133.9
34 .874090 133.4 .874200 132.8
35 .875883 132.2 .873994 131.6
36 .877684 131.0 .877995 130.4
37 .879492 129.8 .879603 129.1
38 .881307 128.5 .881419 127.9
39 .883129 127.3 .883241 126.7
40 .884960 126.0 .885072 125.4
40B .884888 126.0 .885000 125.4
41 .886689 124.8 .886801 124.2
42 .888497 123.5 .888609 122.9
43 .890312 122.2 .890425 121.6
44 .892135 120.9 .892248 120.3
45 .893965 119.6 .894078 119.0
46 .895803 118.3 .895916 117.6
47 .897647 116.9 .897761 116.3
48 .899509 115.6 .899614 114.9
49 .901360 114.2 .901417 113.5
50 .903229 112.8 .903343 112.1
50B .903186 112.8 .903300 112.1
51 .905024 111.4 .905138 110.7
52 .906869 110.0 .906983 109.3
53 .908722 108.6 .908837 107.9
54 .910582 107.1 .910697 106.5
55 .912450 105.6 .912565 105.0
56 .914326 104.2 .914441 103.5
57 .916209 102.7 .916323 102.0
58 .918100 101.3 .918216 100.5
59 .919999 99.7 .820115 98.9
60 .921906 98.1 .922022 97.4
60B .921884 98.1 .922000 97.4
61 .923760 96.6 .923877 95.9
62 .925643 95.0 .925760 94.2
63 .927534 93.3 .927652 92.6
64 .929433 91.7 .929550 90.9
65 .931339 90.0 .931457 89.2
66 .933254 88.3 .933372 87.5
67 .935176 86.5 .935294 85.8
68 .937107 84.7 .937225 84.0
69 .939045 82.9 .939163 82.2
70 .940991 81.1 .941110 80.3
70B .940981 81.1 .941100 80.3
71 .942897 79.2 .943016 78.4
72 .944819 77.3 .944938 76.5
73 .946749 75.3 .946869 74.5
74 .948687 73.3 .948807 72.5
75 .950634 71.2 .950753 70.4
76 .952588 69.0 .952708 68.2
77 .954550 66.8 .954670 66.0
78 .956520 64.4 .956641 63.5
79 .958498 61.9 .958619 61.1
80 .960485 59.4 .960606 58.5
80B .960479 59.4 .960600 58.5
81 .962433 56.7 .962555 55.8
82 .964395 53.9 .964517 53.0
83 .966366 50.9 .966488 50.0
84 .968344 47.8 .968466 47.0
85 .970331 44.5 .970453 43.8
86 .972325 41.0 .972448 40.4
87 .974328 37.5 .974451 36.9
88 .976340 34.0 .976463 33.5
89 .978359 30.6 .978482 30.1
90 .980386 27.2 .980510 26.7
90B .980376 27.2 .980500 26.7
91 .982371 23.9 .982496 23.6
92 .984374 20.8 .984498 20.5
93 .986385 17.7 .986510 17.4
94 .988404 14.8 .988529 14.5
95 .990431 12.0 .990557 11.7
96 .992468  9.3 .992593  9.0
97 .994512  6.7 .994637  6.5
98 .996565  4.1 .996691  4.0
99 .998626  1.8 .998752  1.6
100 1.000696  0.0 1.000822  0.0

In the above table for Sikes’s hydrometer two densities are given corresponding to each of the degrees 20, 30, 40, 50, 60, 70, 80 and 90, indicating that the successive weights belonging to the particular instrument for which the table has been calculated do not quite agree. The discrepancy, however, does not produce any sensible error in the strength of the corresponding spirit.

A table which indicates the weight per gallon of spirituous liquors for every degree of Sikes’s hydrometer is printed in 23 and 24 Vict. c. 114, schedule B. This table differs slightly from that given above, which has been abridged from the table given in Keene’s Handbook of Hydrometry, apparently on account of the equal divisions on Sikes’s scale having been taken as corresponding to equal increments of density.

Sikes’s hydrometer was established for the purpose of collecting the revenue of the United Kingdom by Act of Parliament, 56 Geo. III. c. 140, by which it was enacted that “all spirits shall be deemed and taken to be of the degree of strength which the said hydrometers called Sikes’s hydrometers shall, upon trial by any officer or officers of the customs or excise, denote such spirits to be.” This act came into force on January 5, 1817, and was to have remained in force until August 1, 1818, but was repealed by 58 Geo. III. c. 28, which established Sikes’s hydrometer on a permanent footing. By 3 and 4 Will. IV. c. 52, § 123, it was further enacted that the same instruments and methods should be employed in determining the duty upon imported spirits as should in virtue of any Act of Parliament be employed in the determination of the duty upon spirits distilled at home. It is the practice of the officers of the inland revenue to adjust Sikes’s hydrometer at 62° F., that being the temperature at which the imperial gallon is defined as containing 10 ℔ avoirdupois of distilled water. The specific gravity of any sample of spirits thus determined, when multiplied by ten, gives the weight in pounds per imperial gallon, and the weight of any bulk of spirits divided by this number gives its volume at once in imperial gallons.

Mr (afterwards Colonel) J. B. Keene, of the Hydrometer Office, London, has constructed an instrument after the model of Sikes’s, but provided with twelve weights of different masses but equal volumes, and the instrument is never used without having one of these attached. When loaded with either of the lightest two weights the instrument is specifically lighter than Sikes’s hydrometer when unloaded, and it may thus be used for specific gravities as low as that of absolute alcohol. The volume of each weight being the same, the whole volume immersed is always the same when it floats at the same mark whatever weight may be attached.

Besides the above, many hydrometers have been employed for special purposes. Twaddell’s hydrometer is adapted for densities greater than that of water. The scale is so arranged that the reading multiplied by 5 and added to 1000 gives the specific gravity with reference to water as 1000. To avoid an inconveniently long stem, different instruments are employed for different parts of the scale as mentioned above.

The lactometer constructed by Dicas of Liverpool is adapted for the determination of the quality of milk. It resembles Sikes’s hydrometer in other respects, but is provided with eight weights. It is also provided with a thermometer and slide rule, to reduce the readings to the standard temperature of 55° F. Any determination of density can be taken only as affording prima facie evidence of the quality of milk, as the removal of cream and the addition of water are operations which tend to compensate each other in their influence on the density of the liquid, so that the lactometer cannot be regarded as a reliable instrument.

The marine hydrometers, as supplied by the British government to the royal navy and the merchant marine, are glass instruments with slender stems, and generally serve to indicate specific gravities from 1.000 to 1.040. Before being issued they are compared with a standard instrument, and their errors determined. They are employed for taking observations of the density of sea-water.

The salinometer is a hydrometer originally intended to indicate the strength of the brine in marine boilers in which sea-water is employed. Saunders’s salinometer consists of a hydrometer which floats in a chamber through which the water from the boiler is allowed to flow in a gentle stream, at a temperature of 200° F. The peculiarity of the instrument consists in the stream of water, as it enters the hydrometer chamber, being made to impinge against a disk of metal, by which it is broken into drops, thus liberating the steam, which would otherwise disturb the instrument.

The use of Sikes’s hydrometer necessitates the employment of a considerable quantity of spirit. For the testing of spirits in bulk no more convenient instrument has been devised, but where very small quantities are available more suitable laboratory methods must be adopted.

In England, the Finance Act 1907 (7 Ed. VII. c. 13), section 4, provides as follows: (1) The Commissioners of Customs and the Commissioners of Inland Revenue may jointly make regulations authorizing the use of any means described in the regulations for ascertaining for any purpose the strength or weight of spirits. (2) Where under any enactment Sykes’s (sic) Hydrometer is directed to be used or may be used for the purpose of ascertaining the strength or weight of spirits, any means so authorized by regulations may be used instead of Sykes’s Hydrometer and references to Sykes’s Hydrometer in any enactment shall be construed accordingly. (3) Any regulations made under this section shall be published in the London, Edinburgh and Dublin Gazette, and shall take effect from the date of publication, or such later date as may be mentioned in the regulations for the purpose. (4) The expression “spirits” in this section has the same meaning as in the Spirits Act 1880.  (W. G.) 


HYDROPATHY, the name given, from the Greek, to the “water-cure,” or the treatment of disease by water, used outwardly and inwardly. Like many descriptive names, the word “hydropathy” is defective and even misleading, the active agents in the treatment being heat and cold, of which water