Resumen de 50, 100 & 150 years ago.

• The article discusses innovations and discoveries related to science and published in the journal years ago. In 1967 "monkey law" of Tennessee was prohibiting teaching of evolution in the state's public schools has been repealed. In 1917, it has been suggested to maintain an aerial patrol along the routes followed by shipping, seaplanes and dirigibles taking their supplies of bombs and fuel from mother ships of the class.