Three documents referring to the development of the telescope are discussed. They are arranged with respect to the gradual development of this optical device and its production in London. Document I is a letter written by Beal on 24th November, 1656. It refers only to the Dutch or Galilean telescope and gives interesting details regarding the hand-glass used by Gustavus Adolphus and the taste shown by the English opticians of 1656 in decorating the bodies of Galilean telescopes. Document II is a photographic reproduction of J. Wiesel's price list of 1647. It is by far the most important from the historical standpoint. From it we learn some details of the industrial development of Wiesel's telescope factory in Augsburg at the surprisingly early date of 1647. Document III is a letter written by the well-known London optician Richard Reeves on 11th March, 1660. It informs us of the state of telescope manufacture in London at that time. The prices given for the three kinds of telescopes - Dutch or Galilean, Keplerian, and Schyrlean - are quite reasonable and much lower than those quoted in Document II.