CHEMICAL AND PHYSICAL NOTES. 117 
ture wn situ is £°°3C., then the density in sttw is 1°02464 + 0°00187 
= 1:02651. These examples will make the use of the table perfectly 
plain. 
Having described the construction and the use of the absolute 
weight hydrometer, the following general observations regarding its 
TasLe [X.—Guivine 1n Units or THE Firra DECIMAL PLACE THE DIFFERENCE 
BETWEEN THE Density at 15°°56 C. OF AN AVERAGE SEA-WATER AND ITS 
DENSITY AT ANY OTHER TEMPERATURE BETWEEN 0° C. AND 30° C. 
0° 1° 2° 3° 4° 5° GO 3 Ge 8° g° 10° 1° 12° 13° | aa? 
i 15° 
“0°; 218 | 213 | 207 | 199 | 190 | 179 | 168 | 155 | 141 | 126 | 110) 92 74 54 B4 | 13 
*] | 218 | 213 | 206 | 198 | 189 | 178 | 167 | 154 | 140 | 125 | 109 | 91 1 52 32 | IL 
‘2 | 217 | 212 | 205 | 197 | 188 | 177 | 166 | 153 | 188 | 123 | 107 | 89 70 50 30 9 
‘3B | 217 | 211 | 205 | 196 | 187 | 176 | 165 | 151 | 187 | 122 | 105 | 87 68 48 28 7 
“4 | 216 | 211 | 204 | 195 | 186 | 175 | 164 | 150 | 135 | 120 | 103 | 85 | 66 46 26° «5 
*5 | 216 | 210 | 203 | 195 | 185 | 174 | 163 | 148 | 134 | 119 | 102 | 84 64 44 24 2 
*6 | 215 | 209 | 202 | 194 | 184 | 173 | 161 | 147 | 182 | 117 | 100 | 82 62 42. 22 
‘7 | 215 | 209 | 201 | 193 | 183 | 172 | 160 | 145 | 181 | 116 98 | 80 60 40 20 
“8 | 214 | 208 | 201 | 192 | 132 | 171 | 158 | 144 | 129 | 114 96 | 78 58 38 18 
‘9 |) 214 207 | 200 191 | 181 | 170 | 157 | 142 | 128 | 112 94 | 76 56 36 16 
15° 16° | 17? 18° 19° 20° 212 I 22 232: 24° ‘252 269 | 27° 28° 29° 30° 
“OF 10 | 33 58 84 | 110 | 187 | 164 | 192 | 220 | 249 | 279 | 310 | 341 | 373 | 405 
1 12 | 36 61 87 | 113 | 140 | 167 | 195 | 223 | 252°} 282 | 313 | 344 | 376 | 408 
2 15 | 38 63 89 | 115 | 142 | 170 | 198 | 226 | 255 | 285 | 316 | 347 | 379 | 411 
a V7 | 40 66 92 | 118 | 145 | 172 ; 200 | 229 | 258 | 288 | 819 | BAL | 383 | 415 
4 12 | 43 68 94 | 121 | 148 | 175 | 203 | 232 | 261 | 291 | 322 | 354 | 386 | 418 
i) 22 | 46 71 97 | 123 | 150 | 178 | 206 | 235 | 264 | 2h4 | 325 | 357 | 389 | 421 
‘6: 1 24 ' 48 74 | 100 | 126 | 153 | 181 | 209 | 237 | 267 | 298 | 329 | B60 | Bu2 | 424 
a 3 26 | 50 76 | 102 | 129 | 156 | Ist i 212 | 240 | 270 | 301 | 832 | 363 | 305 | 427 
8 5 US | 53 79 | 105 | 182 | 159 | 186 | 214 | 243 , 273 | 304 | 335 | 367 | 399 | 431 
#Y) 8 3 31 56 81 107 | 134 | 161 | 189 | 217 | 246 | 276 | 807 | 338 | 370 | 402 | 434 
usefulness are taken from the ‘ Retrospect of Oceanography’ (1895) 
already referred to :-— 
“The hydrometer which I constructed for the Challenyrr ex- 
pedition, and used during the whole of it, gives absolute results. 
By its means, the weights of equal volumes of the solution 
and of distilled water of the same temperature are determined 
directly. It is neither more nor less than a pyknometer, where the 
volume of liquid excluded up to a certain mark is weighed instead of 
