A LIVING HISTORY BLOG.

18TH CENTURY LIVING HISTORY IN AUSTRALIA.
Showing posts with label specticles. Show all posts
Showing posts with label specticles. Show all posts

Thursday, 19 May 2011

Kangaroo Dung As Tinder.

Not the best tinder to use, but there is plenty of it about if you can't find anything else. However, I have only used it with reading glass fire lighting.
The lighter dung in the far left pile is what to look for. It is more sun bleached than the other two piles.

A good one!

And some more.


But would you see it on the trail? This is where observation & experience count, it is not something you start practicing when you urgently need to find some tinder.

I found this punk wood beside the trail. Not all punk wood, but enough around the wood to use for making fire, & better than Kangaroo dung.


It actually took longer to make fire than this video shows, but I had to edit. Regardless it did work.

Saturday, 12 March 2011

Lenses.

Here I saw a great trial of the goodness of a burning glass, made of a new figure, not spherical (by one Smithys, I think, they call him), that did burn a glove of my Lord Brouncker’s from the heat of a very little fire, which a burning glass of the old form, or much bigger, could not do, which was mighty pretty.

The Diary of Samuel Pepys Thursday 12 March 1667/68


Francis Smethwick ground the first high-quality aspheric lenses and presented them to the Royal Society on February 27, 1667. A telescope containing four aspheric elements was judged superior to a "common, yet very good" telescope used for comparison, and aspheric reading and burning glasses also outdid their spherical equivalents.
http://www.greatwalloptical.com.hk/optical.page/asphericlens.html


http://hotgates.stanford.edu/Eyes/library/annals50.pdf

 “Mr. Smethwick’s glasses were tried again; and his telescope being compared with another longer telescope, and the object-glasses exchanged, was still found to exceed the other in goodness; and his burning concave being compared with a spherical burning-glass of almost twice the diameter, and held to the fire, it burnt gloves, whereas the other spherical ones would not burn at all.” — “Sir Robert Southwell being lately returned from Portugal, where he had been ambassador from the king, and being desired to acquaint the society with what he had done with respect to the instructions, which he had received from them before his departure from England, related, that he had lodged the astronomical quadrant, which the society had sent to Portugal to make observations with there, with a body of men at Lisbon, who had applied themselves among other kinds of literature to mathematics” March 12th, 1668 (Birch’s “History of the Royal Society,” vol. ii., p. 256).
http://www.pepysdiary.com/archive/1668/03/12/


Author's 17th century specticles.


The Author's reading/burning glass.


One of the author's telescopes.