diff --git a/CubicNoise/Noisers/CubicNoiseEngine.cs b/CubicNoise/Noisers/CubicNoiseEngine.cs
index 5365ea0..7d86729 100644
--- a/CubicNoise/Noisers/CubicNoiseEngine.cs
+++ b/CubicNoise/Noisers/CubicNoiseEngine.cs
@@ -14,7 +14,7 @@ namespace CubicNoise.Noisers
         private readonly int octave;
         private readonly int periodX;
         private readonly int periodY;
-        private int seed;
+        private readonly int seed;
 
         public CubicNoiseEngine(int seed, Dictionary<IParameterName, int> intParameters)
         {