diff --git a/src/SConscript.py b/src/SConscript.py
index e21494fdded1614ab8e8cb8787a2b2dc0c82957a..3d6070dad0fe6d136f34092510ee7b4bd76640b1 100644
--- a/src/SConscript.py
+++ b/src/SConscript.py
@@ -23,6 +23,7 @@ THcDCLookupTTDConv.cxx THcDCTimeToDistConv.cxx \
 THcShower.cxx THcShowerPlane.cxx \
 THcRawShowerHit.cxx \
 THcAerogel.cxx THcAerogelHit.cxx
+THcFormula.cxx
 """)
 
 pbaseenv.Object('main.C')