22 votes

What type of abrasive grit was used to grind lenses for telescopes?

There is an entire article devoted to your query: From "Lens Making for Scientific Instrumentation in the Seventeenth Century" by Silvio A. Bedini (it is behind pay-wall), Appl. Opt. 5, 687-...
  • 3,436
15 votes

What type of abrasive grit was used to grind lenses for telescopes?

One of the early publications covering the topic is Pere Cherubin d'Orleans, La Dioptrique Oculaire, ou La Theorique, La Positive, et La Mechanique, de l'Oculaire Dioptrique en Toutes Ses Especes. ...
  • 3,866
7 votes

When did people notice the special shapes of snowflakes, and when did they start to study them?

There is a very nice site SnowCrystals.com run by Kenneth Libbrecht, a professor of physics at Caltech, which covers both physics and history, and hosts many captivating images, videos and more. ...
  • 69.5k
5 votes

When was double-paned glass first invented and used for insulation?

lmgtfy google cache of mimivanderhave.com 1945 The first double-pane, insulated window was introduced That's without attribution; door and window claims From single to double pane windows… ...
2 votes
Accepted

What is the explanation of rope's strength in Galileo's Two New Sciences?

In this passage Galileo is explaining how a bundle of multiple short fibers twisted into a rope functions. He is analogizing a fiber in the bundle to a fiber held between fingers, and notes that it ...
  • 69.5k
2 votes
Accepted

Who discovered anisotropic materials, and what were they studying?

It depends on what counts as "discovery". Interestingly, optical anisotropy was discovered before the elastic one, and the first anisotropic "material" modeled was... the luminiferous ether. ...
  • 69.5k
2 votes

To what degree did ancient Egyptians use Cement Chemistry

Davidovits' theory appears to be moving slowly from fringe toward mainstream. Also the possibility of a mixed technique i.e. some carved stones along with cast blocks offers a compromise in the ...
  • 2,337
1 vote

Was metallurgy of Zinc first started in India?

Zinc is principally known anciently from the production of brass which was widespread in the ancient world. The way that brass is made is that copper is combined with calamine (zinc oxide, a common ...
1 vote

Early history of the phase concept in the physical sciences

The term `phase' appears to have been coined by J. Willard Gibbs: ``In considering the different homogeneous bodies which can be formed out of any set of component substances, it is convenient to have ...
  • 11

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