CORRESPONDENCE
... CORRESPONDOCE. SEA FOG-SIGNALS. TO THE EIDITORS OF THE iIVEDOOI MEIRCURY. Gentlemen,-Havitig read In the Eaoeniner of the Saturdy before last avery instructive letter by Mt. Blackburn, on ses' fog-signals, wherein he clearly demonstrates the superiority of llgbt over sound for.-sguals in a fog at se%, I beg to state that some time agoe 1. recommended for an allarmlsin-16i to warn a following ...