NIGHT LETTER • DICCIONARIO INGLES.COM • Definition of Night letter

... the conditions which accounts for the growing use of the telegraph. Another is to be found in the recognition of the convenience of the night letter and day letter. This has brought about a considerable increase in the volume of family and social correspondence by telegraph, which will grow to very much greater proportions as experience demonstrates its value. In business life the night letter and day letter have likewise ...

— Masters of Space - Morse, Thompson, Bell, Marconi, Carty • Walter Kellogg Towers