IN the article on “The Disaster to the Airship R38” in NATURE of September 1, the author laments that, in consequence of it, airship development is to be abandoned by our, Government, and airship design is referred to as being a matter of experience and guessing. In face of the general tenor of the article, it may be of interest to direct attention to six letters published in Engineering in November and December, 1901, which I wrote in a discussion of the torpedo-boat destroyer Cobra. Those letters are as applicable to the R38 as to the Cobra.