On 2010/08/17, at 07:55 , Martin Vlietstra wrote:
Many people might be familiar with the “Jerry can”. I understand
that it was so named because if was developed by the German forces
during WWII – it was much more ergonomically designed that the
equivalent Allied equipment and the design was quickly copied.
BTW, the Jerry can hold 20 litres.
Dear Martin and All,
As I understand it the 'Jerry Can' was a decimal division of the 200
litre drum that is still in common use. This drum was designed to hold
200 litres of liquid and to have an air space of about 8 litres to
allow for expansion (I think that oil and oil products have fairly
high coefficients of expansion but please correct me if I am wrong).
Matching the 200 litre drum and the 20 litre 'Jerry Can' gave the
convenience of being able to do decimal calculations of fuel
requirements in a military setting. There is an interesting history of
the 'Jerry Can' at http://en.wikipedia.org/wiki/Jerrycan but no
mention is made of the oil drum in this article.
The 200 litre drum came to be called the 55 gallon drum in the USA
(200 ÷ 3.8 = 52.6 USA gallons) and the 44 gallon drum in the UK and
the Commonwealth countries (200 ÷ 4.5 = 44.4 UK gallons). It is common
to see four-wheel drive vehicles in Australia with two welded frames
on their backs that are designed to carry two of the 20 litre 'Jerry
Cans' often with one for fuel and one for water.
The idea of having a large (about 200 L) and a small (about 20 litre)
container goes back a long way. Consider this quotation from the Bible
with my comments from http://www.metricationmatters.com/docs/MetricationTimeline.pdf
Ezekiel 45
Ye shall have just balances, and a just ephah, and a just bath.
The ephah and the bath shall be of one measure, that the bath may
contain the
tenth part of an homer, and the ephah the tenth part of an homer: the
measure
thereof shall be after the homer.
Here's another decimal division but with two names this time — bath
for wet goods and ephah for dry goods. … It is curious that the homer,
at about 200 litres, is nearly the same size as the standard 200 litre
petrol and oil drum designed in Germany in the 1930s. The bath, at one
tenth of this amount, is equivalent to the small square-shaped fuel
carrier that became known in many English-speaking countries as the
'jerry-can' from its German origins. For most of the 20th century, the
200 litre drum was known as a 44 gallon drum in the UK and its
colonies, and as the 55 gallon drum in the USA because of their
gallons of different sizes.
Cheers,
Pat Naughtin
Author of the ebook, Metrication Leaders Guide, see
http://metricationmatters.com/MetricationLeadersGuideInfo.html
Hear Pat speak at: http://www.youtube.com/watch?v=_lshRAPvPZY
PO Box 305 Belmont 3216,
Geelong, Australia
Phone: 61 3 5241 2008
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