Lady Gertrude Denman, daughter of the Viscount and Viscountess Cowdray, was the founding president of the Women's Institute in 1916.
In the autumn of 1939, after war broke out, she told the WIs they would play an important part in the production and preservation of the country's food, bottling and preserving surplus fruit and vegetables.
The National Federation of Women's Institutes had been given a grant of £500 by the Ministry of Agriculture in 1938 to set up a Produce Guild to teach members about intensive cultivation and to supply fertilisers and plants more cheaply.
Through courses across the country, members were not only shown how to grow more produce but how to start jam making, bottling and canning.
Sugar worth £1,400 was purchased in 1940 and distributed to WIs for the Co-operative Fruit Preservation Scheme. As a result, 1,631 tons of preserves were made that year.
The grant from the Ministry was increased and by 1944, the federation had received £2,100 for national work and £4,000 for work in the counties.
Federations bought canning machines to loan to Institutes and the Associated Countrywomen of the World sent 500 Dixie hand sealers from America for home canning, along with other equipment.
Midhurst Museum has one of these very machines on show in the wartime display put together by curator David Rudwick.
David said: "The museum display will run until the end of November, from 10.30am to 3pm, Tuesday to Saturday. One of the rarest items is the machine to can fruit and vegetables, donated by Midhurst WI.
"We have gas masks, including the Micky Mouse one for children, and a toddler's one where an adult had to pump air all the time. There is the local ARP gas alarm rattle and gas alarm bell saved from the old council offices, and used shell cases that were turned into ornaments and vases, known as trench art."
You can see first aid cases still with unused items inside and a tin of dried egg powder, still full. There are helmets, goggles, gas eye shields, trenching tools and so much more to see.
In the main entrance are the military helmets unearthed by Bellway Homes during the construction of Perceval Grange, off Bepton Road, last autumn.
During the war, Midhurst was an important strategic location and a range of defensive fortifications were put in place in the area in case of an invasion on the south coast.
Bellway unearthed more than 25 of concrete anti-tank obstacles at a roundabout near the entrance to the site and more towards the back fence line.
The northern part of the Perceval Grange site was a brickworks between 1913 and 1985, with the southern part of the site more recently used as a West Sussex County Council depot.