SATISH CHANDRA, C.J. - (1.) THE question which requires our consideration is whether T. squares and drawing-boards fell within the purview of the phrase "mathematical survey instruments" which are exempt under Notification No. S.T.-911/X dated 31st March, 1956. THE Assistant Commissioner (Judicial) held that T. Squares and drawing-boards were mentioned at serial number 160 of the Manual or Orders of the Irrigation Department, U.P., as "survey and mathematical instruments". He felt that this was strong evidence to show that T. squares and drawing-boards were survey and mathematical instruments. He further held that simply because these things may be used for some other purposes also, will not take them out of the category of "survey and mathematical instruments". He, therefore, allowed the appeal and directed the turnover of these things to be exempt from sales tax. THE Judge (Revisions) affirmed this view. It observed that he had taken the same view in several other cases also. THE question of law mentioned by us at the beginning has been referred at the instance of the Commissioner of Income-tax (sic). It is not disputed that in the Manual of Orders of the Irrigation Department, U.P., T. squares and drawing-boards have been mentioned as "survey and mathematical instruments" at page 160. THE normal use of T. squares and drawing-boards appears to be for survey and mathematical purposes. THE authorities were, therefore, justified in holding that the turnover of these things was exempt from tax. We, therefore, answer the question referred to us in affirmative in favour of the assessee and against the department. since no one has appeared on behalf of the assessee, there will be no order as to costs. Reference answered in the affirmative.;