paper & plastics
vintage plastics and ephemera


Silverloy dental proportion scale

Claudius Ash advertising coasters
Claudius Ash Dental advertising coasters
Back of dental advertising coasters
Back of dental advertising coasters


These are a set of proportional scales for use in dentistry. I am not an expert but I would think that the mercury is put in one end and the other materials in the other. They do not weigh specific amounts but as the name suggests they measure the relative proportions of the ingredients. There is a small screwed weight on the arm which would give extremely fine adjustment. In the arm is a channel linking the two bowls and so I assume that when the amounts have been measured the mercury is then run along the channel to mix with the ingredients in the other bowl.

They are made by Crescent Dental Mfg Co of Chicago, USA and are marked as Silverloy Proportion Scale. The base and the arm are of black bakelite with the other components in chromed steel. Overall they are quite small, the arm is only 150mm long and overall they are just over 40mm high.

The scales are in good condition, a couple of small fleabites in the bakelite but nothing significant. They are in the condition that I found them and so they would look better if they are cleaned, but I have left them uncleaned so that whoever buys them can decide whether or not to clean them. I have no idea how old they are but I don't think that free running liquid mercury has been used in dentistry for quite a few years.

These are quite an unusual item and would be good for anyone collecting old dentist's equipment.

Price 45.00.
Postage & packing for UK 3.50.