Resumen de 50, 100 & 150 years ago.

• A retrospective of the articles that appeared in previous issues of "The Scientific American" is presented. The articles include topics on in-vitro fertilization that appeared in the August 1966 issue and the electrification of the Puget Sound lines of the St. Paul Railway in Washington state that appeared in the August 1916 issue. Telegraphic communication through the Atlantic Cable and the construction of a new abattoir in New York City from the August 1866 issue are also mentioned.