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Book, page 352 / 445 lots constituting the consignment in suspected. The size of the lumps constituting a sample will be referred to later. The British Association's regulations lead to a sample weighing about 3 lb. being obtained from each drum. If only one drum is sampled, the quantity taken from each position may be increased with advantage so as to give a sample weighing about 10 lb., while if a large number of drums is sampled, the several samples should be well mixed, and the ordinary method of quartering and re-mixing followed until a representative portion weighing about 10 lb. remains. A sample representative of the bulk of the consignment having been obtained, and hermetically sealed, the procedure of testing by means of the apparatus already described may be given from the German Association's directions: "The first carbide receptacle is filled with 300 to 400 grammes (say 3/4 lb.) of any readily decomposable carbide, and is hung up in the apparatus in such a position with regard to the slot _e_ on the disc _d_ that it will be the first receptacle to be discharged when the winch _i_ is turned. The tin or bottle containing the sample for analysis is then opened and weighed on a balance capable of weighing exactly to 1/2 gramme (say 10 grains). The carbide in it is then distributed quickly, and as far as may be equally, into the nine remaining carbide receptacles, which are then shut and hung up quickly in the generator. The lid _b'_ is then screwed on the generator to close it, and the empty tin or bottle, from which the sample of carbide has been removed, is weighed. "The contents of the first carbide receptacle are then discharged by turning the winch _i_. Their decomposition ensures on the one hand that the sealing water and the generating water are saturated with acetylene, and on the other hand that the dead space in the generator is brought under the pressure of the seal, so that troublesome corrections which would otherwise be entailed are avoided. After the carbide is completely decomposed, but not before two hours at least have elapsed, the cock _p_ is shut, and the gasholder is run down to the zero mark by opening the cock _q_. The cock _q_ is then shut, _p_ is opened, and the analytical examination proper is begun by discharging the several carbide receptacles by turning the winch _i_. After the
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