ফেইসবুক পেইজ ভিজিট ও লাইক দিন। মাননীয় উপদেষ্টা Ramsden's theodolite represented an incredible step ahead while in the instrument's precision. William Gascoigne invented an instrument that applied a telescope using an installed crosshair being a concentrate on unit, in 1640. James Watt developed an optical meter to the measuring https://fredf186wem2.elbloglibre.com/profile