如图所示，\(F_{1}\)是抛物线\(C\)：\(y^{2}=4x\)的焦点，\(F_{i}\)在\(x\)轴上，\((\)其中\(i=1\)，\(2\)，\(3\)，\(…n)\)，\(F_{i}\)的坐标为\((x_{i},0)\)且\(x_{i} < x_{i+1}\)，\(P_{i}\)在抛物线\(C\)上，且\(P_{i}\)在第一象
限\(\triangle P_{i}F_{i}F_{i+1}\)是正三角形．
\((\)Ⅰ\()\)证明：数列\(\{x_{i+1}-x_{i}\}\)是等差数列；
\((II)\)记\(\triangle P_{i}F_{i}F_{i+1}\)的面积为\(S_{i}\)，证明：\( \dfrac {1}{S_{1}}+ \dfrac {1}{S_{2}}+ \dfrac {1}{S_{3}}+…+ \dfrac {1}{S_{n}} < \dfrac {3}{8} \sqrt {3}\)．