Optical Squares

Optical Square by Kilpatrick and Co London.

​Although there are several references to Kilpatrick and Co in Melbourne between 1853 to 1925 there is very little information about the business in London.

I would estimate that this instrument would be circa 1890.

MDS Optical Square

Couldnt find much on this London Manufacturer when searching the Web.

​Circa 1940

 Optical Square by Otto Boettger 

Otto Boettger 88 Flinders Street, Adelaide. South Australia first established in 1877 and was still in business in the 1960s

Optical Square by Salmoiraghi

​This optical square is tiny and simple.

It is engraved " Ing.A.Salmoiraghi & Co, Milano"

I estimate that this is circa 1900.