Surya Siddhanta
एकाकी योजयेद् बीजम् यन्त्रे विस्मयकारिणि। शङ्कुयष्टिधनुश्चक्रैश् छायायन्त्रैर् अनेकधा॥
When quite alone, one should apply quicksilver to the wonder-causing instrument. By the gnomon (shanku), staff (yashti), arc (dhanus), wheel (cakra), instruments for taking the shadow, of various kinds.
english translation