graphite, walnut ink, acrylic paint Since we’re still waiting for plankton I decided to draw these bottles which are used to store water samples for testing for dissolved oxygen. I really enjoy the old fashioned, but still scientific, look of the brown bottles with ground glass stoppers and cream colored stopper leashes in their special wooden crate. Leave a Reply Cancel Reply Your email address will not be published. Name* Email* Website Comment Notify me of follow-up comments by email. Notify me of new posts by email.