The material is to be treated with suitable solvents to remove the oil, varnish and other media, and the residue to be dried at one hundred degrees Centigrade and thoroughly mixed. A weighed quantity of this extracted, dried and mixed material is to be continuously shaken for one hour, at the common temperature, with one thousand times its weight of an aqueous solution of hydrochloric acid containing 0·25 per cent. by weight of hydrogen chloride. This solution is thereafter to be allowed to stand for one hour and then filtered. The lead salt contained in the clear filtrate is then to be precipitated as lead sulphide and weighed as lead sulphate.

1. a

   Every winch, and every derrick with the whole of the gear accessory thereto, shall be tested with a proof load which shall not be less than the following—

   Safe working load	Proof load
   Under 20 tons	25 per cent.	in excess of the safe working load
   20–50 tons	5 tons
   over 50 tons	10 per cent.

   In the case of a derrick with its accessory gear the proof load shall be applied as follows:—

   1. i

      where reasonably practicable by hoisting movable weights; or

   2. ii

      in other cases by maintaining the load by means of an accurate spring or hydraulic balance or similar device for a period of not less than five minutes. Where movable test weights are used the derrick shall be swung, with the load suspended, as far as possible in both directions. Where a spring or hydraulic balance or similar device is employed it shall be sufficient if the proof load is applied with the derrick swung as far as practicable first in one direction and then in the other. In each case the derrick shall be tested at the smallest angle to the horizontal at which it will operate and this angle shall be stated in the certificate of the test.

2. b

   Every crane, crab, sheer-legs, teagle, transporter or runway, with its accessory gear, shall be tested with a proof load which shall not be less than the following—

   Safe working load	Proof load
   Under 20 tons	25 per cent.	in excess of the safe working load
   20–50 tons	5 tons
   over 50 tons	10 per cent.

   In the case of a crane having a variable radius it shall be tested with a proof load applied at the maximum and minimum working radii. At each such radius the crane shall be swung as far as possible in both directions with the corresponding proof load suspended. In the case of hydraulic cranes where, owing to the limitation of pressure it is impossible to hoist a load 25 per cent. in excess of the safe working load, it shall be sufficient to hoist the greatest possible load.

3. c

   Every article of lifting gear (whether it is accessory to any lifting appliance or not) and every pulley block other than a pulley block specially constructed for use with a crane to which it is permanently attached, and every chain shall be tested with a proof load at least equal to that shown against it in the following table:—

   Article of gear	Safe working load	Proof load
   Chain sling		Twice the safe working load
   Rope sling
   Plate clamp
   Ring
   Link
   Hook (other than a ramshorn hook)
   Shackle
   Swivel
   Eye-bolt
   Ramshorn hook	Under 50 tons	Twice the safe working load
   	50 tons to 100 tons	Safe working loads plus 50 tons
   	Over 100 tons	One and a half times the safe working load

   Pulley blocks
   Single sheave block		Four times the safe working load
   Multiple sheave block with safe working load up to and including 20 tons		Twice the safe working load
   Multiple sheave block with safe working load over 20 tons up to and including 40 tons		20 tons in excess of the safe working load
   Multiple sheave block with safe working load over 40 tons		One and a half times the safe working load
   Chains (other than calibrated load chains)		Twice the safe working load
   Calibrated load chains		One and a half times the safe working load

4. d

   After being tested as aforesaid, every lifting appliance with the whole of the gear accessory thereto, every article of lifting gear and every chain shall be examined, and the sheaves and the pins of the pulley blocks shall be removed for the purpose of the examination, to see that no part is injured or permanently deformed by the test.

5. e

   In the case of wire ropes, a sample shall be tested to destruction.