In his recent lecture on “ Airship Mooring and Handling,” Captain Butcher refers to certain experiments carried out with the use of models in connection with three-wire mooring. It is, perhaps, useful to add some further details of these special experiments, which were conducted at the National Physical Laboratory.

Mention was made by Captain Butcher of the original or “ fixed ” three-wire system (see Fig. 1), which originated from the emergency mooring of R.9. Its defects lie in the occasional slackening and subsequent impulsive tightening of one or more of the mooring cables when the airship is riding in gusty weather. In the particular modifications introduced by the N.P.L., breakdown due to this contingency is eliminated.