WEIGHT PAINTING - BONES IN 2.63a

I would like to modify the weights of some of the bones to mesh, but I cannot find an ‘add’ or ‘subtract’. I used to find that in the left ‘tools’, near the radius or strength settings, but it must be hidden somewhere new. The manual is incomplete for that subject. Thanks for any clues.

when in weight paint mode just click on the big brush icon and a lot of brushes should pop up including add and subtract

Thanks [ris. Hidden in plain sight.