In message <h98nbf$l80$1@pc-news.cogsci.ed.ac.uk>, Richard Tobin 
 writes
>In article ,
>Paul Martin   wrote:
>
>>0.6nkg = 600ng, which is definitely measurable. You can't use SI units
>>like that.
>
>I don't see why not:
>
>You have: 600ng
>You want: nkg
>        * 0.6
>
>In the past it was common to use "micro-micro-farads" for picofarads.
>
The Americans are somewhat bemused when we British call these 'puffs'.
-- 
Ian