diff --git a/GPy/likelihoods/Gaussian.py b/GPy/likelihoods/Gaussian.py
index ff358b2d..630b5d91 100644
--- a/GPy/likelihoods/Gaussian.py
+++ b/GPy/likelihoods/Gaussian.py
@@ -32,7 +32,7 @@ class Gaussian(likelihood):
         return ["noise variance"]
 
     def _set_params(self,x):
-        self._variance = x
+        self._variance = float(x)
         self.covariance_matrix = np.eye(self.N)*self._variance
         self.precision = 1./self._variance
 
diff --git a/GPy/models/sparse_GP.py b/GPy/models/sparse_GP.py
index d3592d69..6ba74e38 100644
--- a/GPy/models/sparse_GP.py
+++ b/GPy/models/sparse_GP.py
@@ -130,7 +130,7 @@ class sparse_GP(GP):
             dbeta += - 0.5 * self.D * (self.psi0.sum() - np.trace(self.A)/beta*sf2)
             dbeta += - 0.5 * self.D * np.sum(self.Bi*self.A)/beta
             dbeta += np.sum((self.C - 0.5 * mdot(self.C,self.psi2_beta_scaled,self.C) ) * self.psi1VVpsi1 )/beta
-            self.partial_for_likelihood = -dbeta*self.likelihood.precision
+            self.partial_for_likelihood = -dbeta*self.likelihood.precision**2
 
 
     def _set_params(self, p):