during the romantic period, the organ became more symphonic, capable of creating a gradual crescendo. this was made possible by voicing stops in such a way that families of tone that historically had only been used separately could now be used together, creating an entirely new way of approaching organ registration. new technologies and the work of organ builders such as , aristide cavaillé-coll, and henry willis made it possible to build larger organs with more stops, more variation in sound and timbre, and more divisions. for instance, as earlier as in 1808, the first 32' contre-bombarde was installed in the great organ of nancy cathedral, france. enclosed divisions became common, and registration aids were developed to make it easier for the organist to manage the great number of stops. the desire for louder, grander organs required that the stops be voiced on a higher wind pressure than before. as a result, a greater force was required to overcome the wind pressure and depress the keys. to solve this problem, cavaillé-coll configured the english "barker lever" to assist in operating the key action. this is, essentially, a servomechanism that uses wind pressure from the air plenum, to augment the force that is exerted by the player's fingers.