This pH meter was made in 1946 by Cambridge Scientific Instrument Co. Ltd. in London. The company was founded in 1881 and the owner eventually became Horace Darwin, the youngest son of the famous scientist Charles Darwin. It is a portable version that can be used on-site in many different situations. A similar instrument was used by the Chemistry Department of what is now the University of Cambridge. The science of pH measurement began in the 1910s and was further developed in 1926. The pH meter is an electronic scientific instrument used to determine the pH measurements of a solution accurately; the amount of acid and alkaline in it This measurement can have many other applications helping to maintain the appropriate balance for a particular result. For example, it can measure the pH of pharmaceutical medications, soil, swimming pool water and hair shampoos. This Cambridge portable electronic pH instrument was made in 1946 by a company specialising in scientific instruments. It is an early example of much smaller devices used today in many different fields including medicine, and the preservation and conservation of shipwreck artefacts. Flagstaff Hill Maritime Museum and Village's Curator uses a pH meter today in the conservation process of a historic cannon that was recovered from the 1839 wreck of the vessel 'Children'.Scientific instrument, electric Cambridge Portable pH Meter in a polished wooden box with compartments, fold-out doors, and leather carry handle. Includes blue covered Instruction manual with a 'Certificate of Test' inside, and chemicals. Electrodes mounted in compartment. The lid is separate from the base, attached by pins and hinges. A plate inside the lid gives instructions for 'Preparation for Use'. Made by the Cambridge Instrument Company, London, in 1946.Printed on plate: "Cambridge Instrument Co. Ltd, 13 Grosvenor Place, London, S.W.1' Certificate dated: "6-3- 46" (1946)flagstaff hill, warrnambool, maritime museum, maritime village, great ocean road, shipwreck coast, ph meter, cambridge scientific instrument co. ltd, horace darwin, cambridge university, ph balance, scientific instrument, ph measurement

This photo depicts Arthritis Victoria op shop volunteers, Maureen Reid, Gail Bennison, and Renate Kupfe posing for a photo at the Malvern Opportunity Shop.COL medium close up photo of three women inside a shop. The woman on the left is wearing a white shirt with a checked tartan vest; the woman in the centre is wearing a white shirt with small pink flowers; and the woman on the right of the frame is wearing a white t-shirt with a leopard print scarf. They are standing next to one another, in front of some wall shelving. The shelves are filled with soft toys and dolls. To the right of the frame, there are some adjoining shelves which are filled with crockery and bric-a-brac. To the left of the frame, there is a meter box with a typed sign affixed to it. The sign (partially obscured) says, "Items may be changed for other goods to the same value & only if the price tag is still intact". On top of the meter box, there is a framed certificate sitting leaning against the wall. On the bottom right corner of the photo image, there is a date stamp in bright orange digits: "18 4 '02".L to R. Maureen Reid Gail Bennison Renate Kupfe Malvern Op Shop Volunteersarthritis foundation of victoria, afv, opportunity shop, op shop, charity shop, thrift store, teddy bear, soft toys, dolls, clown, crockery, bric-a-brac, volunteers, members, malvern, 2000