error LNK2019: unresolved external symbol "public: __thiscall destructor

Question

I get this error:

Error   1   error LNK2019: unresolved external symbol "public: __thiscall emath::VecN<float,3>::~VecN<float,3>(void)" (??1?$VecN@M$02@emath@@QAE@XZ) referenced in function _main   C:\Users\RobertBerglund\documents\visual studio 2013\Projects\testEnv\testEnv\Source.obj    testEnv

I don't know why, I declared the class destructor in the header emath.h:

template <typename T, const int n>
    class   VecN
    {
    public:
...
//destructor
        ~VecN();
...
};

And then I defined it in emath.cpp:

template <typename T, const int n>
VecN<T, n>::~VecN()
{
    delete _data;
}

It is also maybe worth to mention that the declaration in the header is between:

namespace emath
{
...
}

And before the class definitions in the cpp file I have:

using namespace emath;

Also _data is an array/pointer of type T

After the class declaration I define the folowing type to use in my code:

typedef VecN<float, 3> vec3;

In main() I have:

...
vec3 vec(4.0f);
...
    cout << "vector test:";
    for (int i = 0; i < 3; i++)
        cout << vec[0] << vec[1] << vec[2] << endl;
...

Please let me know if I need to post more parts of my code, thanks in advance !