Vintage Casella London wall mounted wet and dry Hygrometer

Dates c. 1950's I believe

Overall measurement is approx 12 inches by 5 1/2 inches

The temperature range is from -22 to + 55

Not sure what the angled piece of metal is for at the bottom 

Makers name engraved on the front along with the number 94695 C

Still in original retail box and was used in Northgate Grammar School For Boys in Ipswich Suffolk.  

The sale includes an odd page from a hygrometer table, a temperature scale and a 80 page booklet of Hygrometer tables part II as shown

A classic piece of scientific equipment, perfect for any collector 

From a smoke free home.

I only ship / post within the UK Mainland - No Exceptions, but my items can be purchased via Ebays Global Shipping Program.
Plenty of images added for your inspection,
Please study photographs carefully to ascertain condition for yourselves. 
I am not an expert, so may have missed something which is important to you.
Many thanks for looking
Ref: 1330