MadSci Network: Science History

Re: How did Von Jolly get a 6 ton lead sphere to measure G?

Date: Sat Aug 30 04:23:57 2003
Posted By: John Christie, Faculty, Dept. of Chemistry,
Area of science: Science History
ID: 1057127648.Sh

I was unable to find much information on the web. Von Jolly's experiment is briefly 
described here.

What you are wanting to know, though, is more about the lead ball: more of a social/industrial 
question relating to the 19th century: how expensive was lead then? how was it worked? how 
wasteful or otherwise was this particular piece of science?

I do not have specific information about von Jolly's lead ball. Lead has been worked since before 
Roman times. It is a soft metal that melts at a low temperature. It corrodes somewhat with 
continued exposure to air. It is easily cast, rolled, or beaten. Any lead object that is no longer 
useful can easily be reworked by melting.

Although fairly rare, lead has never been particularly expensive, and, relatively speaking, it 
probably cost rather less in the mid 19th century than it does today. I have no specific price 
information for the 1800s. In 1932 lead cost around $US 60 per ton; by 1948 the figure was 
around $US 500 per tonne. It is more expensive now, of course. Late in the 19th century lead 
prices went up as the supply of high grade ores deteriorated. New methods of extraction and 
concentration of ores (flotation methods) became available early in the 20th century, and the 
prices went back down accordingly. The bottom line, though, is that it was not hugely 
expensive, and probably comfortably within von Jolly's research budget (or its 19th century 

A large lead sphere like the one von Jolly used was almost certainly cast in a mould. The sphere 
would have been just under 1 metre in diameter. It doesn't sound terribly useful for other 
purposes: too big for a cannon ball. A bad shape for ship's ballast. You would not want ballast 
rolling around! Probably it was either kept for later physics experiments, or melted down for other 

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