HI - I'm okay with cubic splines but have never had to deal with one with unequal spacings and can't seem to find out how to approach this.

Would anyone be able to offer some advice or point me too somewhere on the web that might?

I thought that maybe taking a linear spline and then using those estimates for the missing value. My data points are:
(1,1.748) (2,2.846) (3,3.992) (4,4.952) (6,5.707) (8,5.029)