Kames Powder Mill started manufacturing gunpowder in 1839 under the ownership of Thomas Gray Buchanan and John McCallum. Production was undertaken at Millhouse in buildings positioned around the four acre site. For safety reasons the remote, rural location was ideal and it had a reliable water source which was needed for power along with access to the Clyde via the pier at Kames for onward shipment of the goods.
The mill operated six days a week with 12 hours Monday to Saturday. It was estimated that 60 to 70 full loads were transported to and from the works from the pier every day by horse drawn trucks. At the height of its production it was the largest local employer employing 150 people.
There were a number of accidents at the site where the gunpowder exploded killing some of the workers. One such explosion took place in 1863 when tons of gunpowder ignited killing seven workers and injuring eight more. The shock of the blasts was felt in Dunoon and Rothesay and could be heard in Inveraray some forty miles away.
The Explosives Act (1875) brought in new safety regulations that all gunpowder manufacturers had to adhere to. The business was bought by Messrs Curtis & Harvey for £25,000 in 1876. They transferred some of the work and employees from the powder mill they owned at Glen Lean, near Sandbank, to Millhouse at this time. There were a number of innovations in gunpowder production and other explosives during this era with the invention of Dynamite (1867), Ballistite (1888) and Cordite (1889) making great changes within the industry.
On Thursday 13 August 1914, the Aberdeen Journal reported:
A Dunoon telegram yesterday stated that a lady who was arrested at Millhouse Gunpowder Works on Sunday as an alleged German spy, has been released. Inquiries disclosed that she was on holiday in the Kyles of Bute, and twice wandered near the magazine.
By the start of the 1920s the mill had been taken over by the Nobel Explosives Company. There was a marked decline in the demand for gunpowder and due to overcapacity in the market the Kames Powder Mill was closed. The machinery was dismantled and some of the buildings were demolished.
During WWII the site was requisitioned by the MOD and became a restricted zone. The Army used the area for training including demolition practice.
Millhouse now has the Dolphin Bell and powder testing mortar/cannon as memorials in the village. The accompanying plaque lists all those who died at the Powder Mill as well as the crew members who drowned when the company steamship the ‘Guy Fawkes’ sank in 1864. The bell is the bronze bell that sat in a cast iron frame with dolphin shaped supports at the factory. It was used as a time keeping device and an alarm in the event of fire or explosion at the site.