Use a refractometer...

[DraggingTail]

Is this refractometer manufactured correctly?

The reason I ask is I would thing the flat side would sit on the prism but the led is glued on the flat side.

See pics

 

[Crabs McJones]

Is this refractometer manufactured correctly?

The reason I ask is I would thing the flat side would sit on the prism but the led is glued on the flat side.

See pics

The raised side opposite of the led light sits on the prism, the prism is slightly recessed in the unit, so the raised part on the glass sits in that recessed prism

 

[DraggingTail]

The raised side opposite of the led light sits on the prism, the prism is slightly recessed in the unit, so the raised part on the glass sits in that recessed prism

I would have thought that too but it is not recessed. Why would the rough surface sit on the prism?
Thanks for the help