Eichler windows leaking rain water

My BIG single pane Eichler windows are leaking rain water around the sills and I am not sure the best way to seal them. In some of the windows it is clear the wood has separated a little allowing the water breach. In other windows the leak location is not so apparent.

A normal window has glazing, but these huge panes of glass are set between flat wood without any visable seal. I thought maybe I could apply a thin bead of clear silicone to the outside and inside glass perimiter.

Any thoughts? thanks!