Abstract: This method of accessing a telephone conference bridge that corresponds to a specific physical call number comprises: a client calling a special number corresponding to a telephone conference service, which number is common to a set of telephone conferences; transferring the call to a service control point; setting up a call between the client and an intelligent peripheral under the control of the service control point; the client sending an access code to the intelligent peripheral, which access code is specific to the telephone conference bridge; the intelligent peripheral forwarding the conference bridge access code to the service control point; the service control point determining which conference bridge corresponds to the supplied access code and allocating the corresponding physical call number to the call; and a call being set up between the client and the determined conference bridge.

Abstract: A method and a device are disclosed for measuring the lithium concentration in the primary cooling circuit of a nuclear power station reactor. The lithium concentration Li.sup.+ is determined by linear correlation between the electrical conductivity .lambda. of the cooling water measured by measuring means 1, at a given temperature t measured by measuring means 2. Means 4 to measure the boron concentration B make it possible, by means of the computing means 3 to determine the lithium concentration Li.sup.+ according to the decreasing lithium hydroxide specification. The invention can be applied to the maintaining and regulation of the pH of the cooling water of a nuclear power station reactor at a determined value.