Doing another AMTMA! Come hang out with us and figure out what we should model! It should be a good time!
2020-05-06T18:00:00Z
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What do YOU think we should model today? Leave an idea below! Remember, we are shooting to do quite a few, so we need as many ideas as you can spare!!
I’m trying to draw Robert Boyle’s 1657(ish) Air Pump. It’s an important early scientific instrument, which he used to explore the effects of reducing air pressure - it pumped air out of the glass ‘air receptacle’.
How would you model the handles on the shut off valve, and the similar handle on the lid on the top of the glass receptacle?
There are very few contemporary drawings of it. This seems to be the one most commonly reproduced.
but here’s a later one that looks clearer.
And here’s a photo of a modern replica.
The handles appear to be round(ish) in cross section and curved as shown in the previous images.
It’s been hard to find information about the size of the object, but I think that it is about 4ft/1.2m tall, and the glass receptacle is about 16-1/2" radius (~22cm).
And the lid is about 4" (100mm) diameter.
This image, from a painting of the object, gives a sense of scale.
Making some rough assumptions, I estimate that the overall height is around 4 feet, or about 1.2m.
If the man with his hand it the air is of average height for the time of (in round numbers) 5ft 6in, his hand is about a foot above the top of his head, and the table is 2ft 6in high (again, a normal sort of height for a table), then the height of the pump is the difference between the height of his hand, and the height of the table, or about 4ft.
Taking that as a starting point, and drawing over one of the images, scaled to 4ft/1.2m high, gives the outer diameter of the glass ‘receiver’ as about 16.5in or 42cm.
The most promising fact I found was that is was said to have a capacity of ‘about 30 quarts’. And a quart was always a quarter of a gallon.
Unfortunately, at that time, a gallon was a variable quantity - three different sizes were still in common use, one each for wine, ale, and dry goods (like grain, flour, sand, etc.). And for some time previously a beer gallon was different from an ale gallon (and I don’t know the difference between ale and beer!).
However, calculating the radius of a sphere that would hold 7 1/2 liquid gallons (30 quarts) of either wine or ale gives an answer surprisingly close to the radius estimated as above, and closer if you allow something for the thickness of the glass for the difference between inside and outside diameter.
Whats about the world famous car from east germany - Trabant 601 aka plastic bomber 
3 Mio Cars build between 1964 and 1990 - the body of the car not changed of the the years - only some small updates introduced as major improvements
I like the family-night painting. Nothing says good fun like watching a bird suffocate.
