Quasielastic electron scattering from<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msup><mml:mrow/><mml:mrow><mml:mn>40</mml:mn></mml:mrow></mml:msup></mml:mrow></mml:math>Ca

Differential cross sections for quasielastic electron scattering on ${}^{40}$Ca have been measured at laboratory scattering angles of 45.5$\ifmmode^\circ\else\textdegree\fi{}$, 90$\ifmmode^\circ\else\textdegree\fi{}$, and 140$\ifmmode^\circ\else\textdegree\fi{}$ with bombarding energies ranging from 130 to 840 MeV. Transverse and longitudinal response functions have been extracted for momentum transfers from 300 to 500 MeV/$c$. Contrary to some previously reported results, the total observed longitudinal strength agrees with the relativistic Fermi gas prediction to within $\ifmmode\pm\else\textpm\fi{}$18%.