THE BAUMfi: HYDIiOMETERS. 67 



(15) .Mauul'acturiiig Chemists' Association, U. S. A. (i()0=1.835. Calculated by A. H. Elliott 

 from the data given by tlie eoinmittee on "What is oil of vitriol?" in 1875, 



(ifjo H = e2SO, !t;5. 5 



H.,0 (i. 5 



1(10.0 



This scale appears in a separate sheet published by the association. In a report of the Coni- 

 inisi?ion on "What is oil of vitriol?" previously published, a tal)le ditl'ering slightly from this is 

 jmblished. 



(16) Schober and Pecher. (j(jo = 1.8340. The mark 10'^ was obtained by a 10 per cent, salt 

 solution of specitic gravity 1.07-t and the scale calculated by the formula 



](),> + , {p-\) 



in which S = specitic gravity of the fluid, />=specitic gravity of salt solution, ;(=degrees. (Dmg- 

 ler's Polyt. J., 1828, vol. '21, 63.) This scale appears in Dingler's I'olyt. J., vol. 27, 63; Hotfmann- 

 Schaedler Tabellen, 1877; Knapp, Ohem. Tech.; E. L. Schubarth, vol. 1, 47. 



(17) Huss, Edinburgh Disjjensatory. 66° = 1.8312. Calculated by Iluss and published in 

 Duncan's Ed'b'gh Disp., 1830. This scale appears in Duncan's Ed'b'gh Disp., 1830; V. S. Dispen- 

 satory, Sth, 7tb, 8th, nth, 12th, 13th, and 14th editions. 



(18) Gerlach. 66°= 1.8171. Based on a 10 per cent, salt solution of specific gravity 1.07311 

 at 14° R. (Dingier Polyt. J., 1870, 198, 315.) Thi.s scale appears in Dingler's Polyt. J., 1870; 

 Post, Chem. Tech. Analyse, 1881, Part 1, 438; Lunge, Soda Industrie, 1870, vol. 1. 



(19) Chemiker Kalender. Berlin. <i6o = 1.815. No method stated. This scale appears in 

 Chem. Kalender, Berlin, Dr. Biedermaun, 1881. 



(20) " Baume Original Scale." As calculated by Gerlach, 1870. 66o=1.7897. Based on the 

 specific gravity of a 15 per cent, salt solution hi vacuo at 15° C. = 1.11146. This scale appears in 

 Dingler's Polyt. J., 1870, vol. 198, 316. 



(21) Baudin. 66o=1.786 (calculated). A 15 per cent, salt solution of specific gravity 1.111 

 was employed for the 15 mark, at 15° C. (Chemical News, 1870, vol. 21, 54.) This scale appears 

 in Chemical News, 1870, vol. 21, .54. 



(22) Francceur. 66o=1.767. The 15 mark was obtained by a 15 per cent, solution of rock salt 

 dissolved in distilled water at maximum density specific gravity = 1.1094. (Francieur, Memoire, 

 sur I'Areometrie, 1842, Paris, 26.) This scale appears in Watts' Diet., vol. 3, 209 ; Johnson's Cycl., 

 vol. 2, 1062; Fownes' Chemistry, 12th ed. ; Ure's Diet., vol. 1; Handwdrterbuch der Chemie, vol. 

 2, 1 ; Knapp, Chem. Tech. ; Bache & McCulloh, 1848. 



(23) Bohnenberger. 66o=1.730 (calculated). Probably a 15 per cent, salt solution at 11.5° R. 

 was employed for the 15 mark. (Wagner, Jahresb., 1869, vol. 15, 235.) This scale appears in 

 Handwiirterbucb der Chemie, vol. 2, 1; Practical Magazine; Dingler's Polyt. J., 1865, vol. 176; 

 Tiib. Bliitter, vol. 2, 457 ; Knapp, Chem. Technology. 



THE TRUE Sf'ALE FOR LIQUIDS HEAVIER THAN WATER. 



As no one of these twenty-three scales had been obtained by following Bauiii^ exactly, it was 

 deemed advisable to repeat his experiments. 



Three solutions were prepcired by following exactly the directions of Baume, each one con- 

 taining 15 per cent, of salt and 85 per cent, of water by weight. For the first solution chemically 

 pure sodium chloride was employed ; for the second, " solar salt," from Syracuse ; for the third, 

 " factory -filled dairy salt," from Syracuse. The specific gravity of these solutions was carefully 

 determined at 10° Reaumur. The results are given in Table III, together with the results obtained 

 by several friends who have rei)eated this experiment, and also of several chemists who have pub- 

 lished their results. 



