The striking watch includes a watch case, which is formed of a middle part and a back cover removably secured to the middle part, and a crystal that closes the case in a sealed manner. In a first embodiment of the method, the objects are immersed in a tank containing coupling fluid and a flow of fluid is generated in the tank beneath the object holder, thereby producing a suction pressure that tends to hold the objects in the holder. The measuring instrument also allows reflection measurements to be carried out, for example on non-transparent substrates or by tilting the measuring head and covering the retro-reflector. An apparatus implementing the method described above. The locking mechanism adheres to the outside of the tube to bear shearing forces on the plunger. Fluid pressure opening applies a discharge pressure to chamber for delivering emulsion explosives composition through outlet to delivery hose for charging blast holes.