Thanks!
The 'magnifying glass stuff' are research points and you can get them by purchasing research sites (the white squares on the left side of the screen) and dragging the bones of dead dinos to them (the game explains this to you once you buy the first research site).
As for the visitors just disappearing, did you check whether your popularity (the number out of five next to the star icon) was at zero when this happened, as the rate at which you get visitors depends on that number? If that wasn't the case, then the bug where the visitors stop spawning in is still in the game and my fix didn't work.