a bose-einstein condensate was produced in a vapor of rubidium-87 atoms that was confined by magnetic fields and evaporatively cooled. the condensate fraction first appeared near a temperature of 170 nanokelvin and a number density of 2.5 x 1012 per cubic centimeter and could be preserved for more than 15 seconds. three primary signatures of bose-einstein condensation were seen. (i) on top of a broad thermal velocity distribution, a narrow peak appeared that was centered at zero velocity. (ii) the fraction of the atoms that were in this low-velocity peak increased abruptly as the sample temperature was lowered. (iii) the peak exhibited a nonthermal, anisotropic velocity distribution expected of the minimum-energy quantum state of the magnetic trap in contrast to the isotropic, thermal velocity distribution observed in the broad uncondensed fraction.