Unless the cover glass is in the box you won't be able to use it as a
counting chamber. But it will be very useful as a stage micrometer for
calibrating an eyepiece graticule. Stage micrometers are usually rather
expensive -- so you've got one very cheaply. But the line spacing
depends on the ruling. It it's very old it might not be 'Improved
Neubauer' (IN) and without the handbook you'll need to do a web search.
I can send you details of the IN ruling if you need them.

Don W

A. S. St Leger wrote:
>
> Hi,
>
> I am prone to place low bids on Ebay items that look worth having if
> the bidding doesn't go higher and on intriguing items. A few minutes
> ago I became the owner of an item listed as a Zeiss blood testing kit
> (the seller wasn't certain about this attribution). It comprises a
> slide and two rubber tubes with attachments, all in a nice box. It
> could well be what the seller thought. However, given that it cost me
> £1.99 (approx $1) I'm not complaining. Can anyone guess what it is?
> Item number: 120128219613
>
> Selwyn
>
>
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--
Dr E D F Williams
http://www.kolumbus.fi/mimosa/
http://personal.inet.fi/cool/don.williams/
P O Box 15, 41660 TOIVAKKA, Finland
Phone: +358400706616