Back in the DHSS

Except it's the DWP these days. ( rant about form-filling )

Staring out of the Window

or, "you should see my 'to do' list".
( picture of today )

Help -- marine biology ...

What is the word to do with consistency / gravity / mass (but not any of these) that fits into the following sentence?
Jellyfish have almost the same __________ as sea water

It's not for me, it's for a (probably overdue) fanzine article ...
EDIT: going with 'density' (thanks flickgc, major_clanger!)
Next question: Why won't bloody Word let me edit my document while I have anything else running?
'sokay, was a rhetorical one. I know the answer and it has to do with some chap or jellyfish named Bill.