This corresponds with the empirical formula previously found, for And therefore the empirical formula is also here the rational formula, viz.— H C12H,N, or = HN phenylamine, or aniline. QUESTIONS given at the Examination for Certificates in Chemistry, held at the South Kensington Museum, in November 1860. [Three hours allowed for this Paper.] INORGANIC CHEMISTRY. SECTION 1. 1. Describe the preparation, properties, and the composition by weight and volume, of nitric oxide. 2. Give an outline of the manufacture of coal gas. 3. Give the composition of the atmosphere, and describe the methods employed in determining its constituents. SECTION II. 1. State the composition of gunpowder, and explain the reaction which takes place during its combustion. 2. Give an outline of the theory of bleaching. 3. A mineral has been found to contain in 100 parts : Sodium Oxygen What is the formula of the mineral? The following equivalents to be used: Solution. Divide the quantity of each element by its equivalent: Dividing each of these results by 38 (the number of eqs. of Ca) we obtain Therefore the compound contains Ca Al, Si, O16, and its composition is CaO, SiO ̧ + AlО3, 3SiO3. SECTION III. 1. Give the composition and the preparation of chloric and perchloric acids. 2. Describe the course of analysis followed in cases of poisoning by arsenic. 3. Give an outliue of the doctrine of chemical equivalents. SECTION IV. 1. How is fluorine detected in the presence of silicates? 2. Give an outline of the manufacture of white lead. 3. Name the more frequently occurring mineral compounds which are insoluble both in water and acids, and describe the process of rendering them soluble for analysis. PRACTICAL EXAMINATION IN ANALYSIS. 1. Qualitative analysis of a mixture consisting of two acids and two bases soluble in water or acids. 2. Qualitative analysis of a mixture consisting of two acids and two bases partly or entirely insoluble in water and acids. 3. Qualitative analysis of more complex mixtures. ORGANIC CHEMISTRY. [Three hours allowed for this Paper.] 1. Describe the several methods of ascertaining the presence of hydrocyanic acid. 2. Give the method of preparing fulminate of mercury, and explain the constitution of this compound. 3. Give an outline of the chemical processes involved in the nutrition of plants. SECTION II. 1. Describe the method of preparing iodide of ethyl. 2. Give an outline of the preparation, properties, and decompositions of urea. 3. Describe Gay Lussac's method of determining vapour densities, and develop the general formula: D= Density of vapour. p = Amount of substance employed. V = Volume of vapour observed in cubic centimetres. to = Temperature observed. B = Barometer normal. b= Barometer observed. h = Suspended mercury-column. a = Weight of 1 cubic centimetre of air. e Coefficient of expansion of air. Solution: It is not intended to enter into the details of Gay Lussac's method of ascertaining the density of the vapour of a volatile liquid; but, in order to render the following formula intelligible, a brief outline of the process is necessary. A graduated glass receiver is filled with mercury and inverted in a vessel containing the same fluid. A few |