Daily Mail Cryptic bare bones Sunday July 31st 2011

[j4ne50]

REALLY STUCK !! arrgghh .. Can somebody help me please.. Thank you.
This is the 'bare bones' crossword, so you don't know how many letters in each word unfortunately. I've done the most .. it's just these..

12a. Sounds as if wood for walking on's fixed-it's important in Physics (two words)(15 letters) --A---S-O-S-A-T.
I'm sure I have the letters right.. I've gone over and over it, but I'm happy to have them checked if your not sure they are. Think it's something 'constant', but don't know what.

12d. No summit overcome with mountaineer's aid. (5letters) ----N.

9a. A reportedly cruel building up.(7letters) --C---L.

[alexanderd]

9 piton

[treetops1]

Plancks Constant ?
http://en.wikipedia.org/wiki/Planck_constant

[Lie-in King]

12a Planck's constant
12d Piton - 'no tip' (over)
9a Accrual - "a cruel"

[boxtops]

9a accrual

[j4ne50]

Wow .. Thank you all .... Is it genii.. or geniuses.. or just genius !..
I have another if you don't mind ....

1a.Public interest boards question a song composition.(7letters) --A-G-S.

16a.One making an effort accommodates small measure to be tidier.(7letters)
T-I---R..

[Mamyalynne]

16 trimmer

[Lie-in King]

1a Quangos - qu(estion) + anag 'a song'
16a Trimmer - 'mm' (millimetre, small measure, in) 'trier'

[Mamyalynne]

Quangos

[j4ne50]

Thanks a lot Lie-in King. Just one question , I had thought of Quangos, but just couldn't see what 'public interest board' had to do with it. Is there any connection ?

Grateful .. but confused j4ne.. :o)

[boxtops]

A quango is a public body mamya though - "a semipublic government-financed administrative body whose members are appointed by the government"