Union two JObjects with JSON.net

Question

What I'm looking to do is union two JObjects with the JSON.net library. An example would be

JObject j = JObject.Parse("{'test':1,'blah':2}");
JObject b = JObject.Parse("{'test':2}");

Would join to form the JSON Object equivalent to

{'test':2, 'blah':2}

Essentially the same operation as jQuery's extend but in JSON.net. I can't seem to find a simple way to do this.