Alahazrat as a Jurist
  Jurisprudence was the main Subject of Imam Ahmad Raza. He was originally a Jurist. 
Fatawa Radhvia consisting 12 Volumes spread over 12000pages in big size is a marvellous work of Imam Ahmad Raza. This is a collection of thousand of Fatawa, Solution of thousands religious issues & problems. This book contains many researches of Imam Ahmad Raza in Fiqh. 
For example Aalahazrat Imam Ahmad Raza has described 306 kinds of water and discussing 
their qualities, Chemical reactions etc, he has proved that with 160 kinds of water Wadhu (Ablution) can be made & with 146 kinds of water the ablution is not permissible. 
Like wise about Tayammum (Alternative of ablution) he has drawn a list of 181 things (Soil & other matters) fit to be used for Tayammum & a list of 130 things unfit for this purpose. This Fatawa Radhvia is an ocean of learning & knowledge. Imam Ahmad Raza has used theories of physics, Geology, chemistry, logarithm, spherical Trigonometry, Algebra and view 
points of trade, commerce & Economics etc in this book. He has made the rational branches of knowledge the slave of Fiqh and Divinity. This is infact a constitution of life .

His another work in Fiqh is "Jiddul Mumtar." "Kiflul Faqihil Fahim" is also a good example of his skill in Fiqh. 
Ulama and Jurist's of his time & the present age have admitted his skill in Fiqh.