Hydrometer, Beaume. Two kinds in use : heavy Beaume, for 

 liquids heavier than water; and light Beaume, for liquids 

 lighter than water. In the former, o corresponds to water, 

 66 to a specific gravity of 1-842. In the latter, o is equi- 

 valent to a 10 per cent, solution of common salt, and 60* 

 to a specific gravity of 0-745. [15.] 



Hydrometer, Fahrenheit's. A glass hydrometer similar to 

 Nicholson's. [15.] 



Hydrometer, Freeboard. A hydrometer used on board ship for 

 correcting the draught of vessels loading in fresh or brackish 

 water. [15.] 



Hydrometer, Lactometer. For milk. [5, 13, 15, 17, 21, 26.] 



Hydrometer, Nicholson's. Made of japanned tin or brass for 

 taking the s.g. of solids, or of glass for liquids. In the former 

 case the solid is placed on the upper pan of the hydrometer 

 and weights are added till the hydrometer sinks to the 

 zero mark. In the latter the glass hydrometer is placed in 

 the liquid under test with a suitable counterpoise attached 

 at the bottom. [15, 17, 21.] 



Hydrometer, Oil (Oleometer). For vegetable and sperm oils. 

 Scale, 5o-o (= 870 to 970). [15.] 



Hydrometer for Rubber Latex. Scale, 970-!, 000. 



Hydrometer, Saccharometer. For determining the specific gravity 

 of sugar solutions. [5, 6, 13, 17, 20, 21, 25, 26.] 



Hydrometer, Sikes's. For determining strengths of alcoholic 

 liquor in glass or brass. Used with tables which convert the 

 hydrometer readings into percentage of proof. 



Hydrometer, Twaddell. For liquids heavier than water. In 6 

 numbers, embracing the range o-i7O T. (To convert T. 

 to specific gravity, multiply by 5 and add i.ooo.) [5, 13, 

 15, 17,21, 28.] 



Hydrometrograph. An instrument for determining and recording 

 the quantity of water discharged from a pipe, orifice, etc., 

 in a given time. 



Hydrophore. An instrument for obtaining specimens of water 

 from any desired depth, as in a river, lake, or ocean. 



Hydrophone. An instrument for detecting sounds through the 

 medium of water. 



Hydropyrometer. A pyrometer (q.v.) in which the temperature 

 is ascertained by exposing to the action of the heat which is 

 measured a definite weight of some metal, as platinum, steel, 

 copper, etc. ; then quenching the same in a known weight 

 of water and noting the rise in temperature of the latter. [5.] 



Hydroscope. An instrument designed to mark the presence of 

 water, especially in air ; also a kind of water-clock used by 

 the ancients for measuring time, the water trickling from an 

 orifice at the end of a graduated tube. 



Hydrostatic Balance. See Balance. 



Hydro Volume Meter. See Meter. 



Hyetograph. See Rain-Gauge 



