We have used solar wind electron heat fluxes to determine the magnetic polarities of the 14 magnetic clouds observed with the ISEE 3 spacecraft in 1978--1982. The clouds have been modeled as single magnetic flux ropes, and it is generally assumed that they are magnetically closed structures with each end of the flux rope connected to the Sun. In that case, the magnetic polarity of each cloud should be unchanged during the passage of ISEE 3 through the cloud. We use the dominant heat flux in bidirectional electron heat fluxes to determine the cloud polarities and find that the polarity changes in at least 2 and possibly 6 of the 14 clouds, meaning that those clouds cannot fit the popular model of a single flux rope. We have also examined the large-scale fields with bidirectional electron fluxes that follow some magnetic clouds. We recently conjectured that these following fields were the trailing legs of flux rope loops. For that picture to be valid, the clouds and their trailing fields must have opposite polarities and matching magnetic chiralities. We use a simple scheme to test for magnetic chiralities of those clouds and their trailing fields and find that only 1 of 8 may have the flux rope loop geometry. ¿ 1999 American Geophysical Union