I'm happy to leave the matter of 'the common good' to the lawyers to sort out, though personally I would see the building of new schools as being in the common good.
How much is £25 k worth nowadays? The answer is that there are different ways of calculating it. Rather than be accused of bias, here is the current value using 5 recognised measures:
In 2004, £25000 0s 0d from 1898 is worth:
£1,804,292.19 using the retail price index
£2,281,304.35 using the GDP deflator
£9,808,252.43 using average earnings
£11,631,852.22 using per capita GDP
£17,235,627.59 using the GDP
So it certainly wasn't a gift.
source -
http://eh.net/hmit/ukcompare/