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Miscellaneous Intelligence. 



its contents until the surface stands at 71, when the finger is to 

 be closed on the top, and the rest of the fluid within put into a 

 large drinking-tumbler in which the mixture with the test-liquor 

 is to be made. This glass should be placed on a sheet of white 

 paper. A measure D, for the test-liquor, each great division, 

 or degree, being equal to the capacity of the measure C. 

 This measure is to be filled above the graduation with the test- 

 liquor; and then the excess dropped out at the beak, which should 

 be greased, or waxed, to make the drops more distinct. E is 

 a measure graduated like the first but inversely, and intended to 

 contain the quantity of test liquor, to be poured suddenly into the 

 chloride. A tube F, contracted at its lower extremity, considerably 

 facilitates the mensuration of the liquid; for by applying the finger 

 at the top, small quantities can be readily added to, or subtracted 

 from, that in the measure, until it coincides with the required 

 degree. 



The test-liquor is made by heating one part of finely* powdered 

 indigo with nine of strong sulphuric acid at 212°, for six or eight 

 hours, and then diluting it until ten volumes of it are decoloured 

 by one volume of chlorine. A liquid containing its volume of 

 chlorine, may be prepared with sufficient accuracy by treating 3.98 

 grammes of oxide of manganese, crystallized in fine needles, with 

 muriatic acid, and receiving the chlorine in a milk of lime, afterwards 

 to be brought to one litre by the addition of water, as was before 

 mentioned; but if great exactness be required, the gas must be 

 prepared, dried, measured, and its volume corrected for tempera- 

 ture and pressure, and then absorbed by a milk of lime. 

 It is highly important to preserve the test-liquid from light. 

 For the trial of the chloride ; take various specimens from 

 the mass of chloride to be examined, and mix them well ; weigh 

 out five grammes, which rub in the mortar with _ 



enough water to make a cream ; then add a fresh ^ 

 portion of water, pour off the upper portion of 

 the mixture into the jar A, taking care 

 to lose none of it ; then add more water to the 

 residue of the chloride in the mortar, rub it 

 again, and repeat this till the whole is mixed 

 up and introduced into the jar ; wash the last 

 portions from the mortar with a little water, and 

 make up the volume to half a litre, which stir 

 well, so as to render it homogeneous. Fill the 

 measure D up to 0° with the proof liquor, 

 and pour into the tumbler such quantity of it to 

 as may be supposed somewhat inferior to that 

 Avhich a measure of the chloride will decolour, 5° for instance. Take 

 a measure of the chloride with the instrument C, and by blow- 

 ing, force it rapidly into the test-liquor, stirring at the same 



