Merge pull request #31 from stormwatch/edit/ask-mass

“Ask” rather than “access”

en/chapter-04/contents.texinfo

@@ -910,10 +910,10 @@ SpaceShip>>gravity
    @return{} [-10 * self mass * self starMass / (position r raisedTo: 3) * position]
       on: Error do: [0 @@ 0]}
 
-Observe the message @smalltalk{#starMass} sent to the space ship. We
-have not yet figured out how to access the star mass from a space ship
-instance. Its @method{starMass} method can just return, for now, the
-constant 8000.
+Observe the message @smalltalk{#starMass} sent to the spaceship herself.
+We, as a spaceship, have not yet figured out how to ask the central star
+for its stellar mass. Our @method{starMass} method can just return, for
+now, the number 8000.
 
 @c Explain the SpaceWar step method
 The game play is the responsibility of a @class{SpaceWar} instance. At