JUDGMENT A. R. TIWARI, J. - At the instance of the department (Commissioner of Sales Tax, Madhya Pradesh) the Tribunal (Board of Revenue) has referred the undernoted common question of law in all these four reference applications for our opinion : "Whether, in the facts and circumstances of the case, the Board of Revenue was justified in holding the sale of monoblock pumping sets at the rate applicable to centrifugal pumps at 3 per cent ?" and at the instance of the assessee (M/s. Rajesh Electricals, Indore), the Tribunal has referred the undernoted common question of law in all these four reference applications for our opinion : "Whether, in the facts and circumstances of the case, the Board of Revenue was justified in holding that coupled pumping sets were not centrifugal pumps and, therefore, not covered by Notification No. 1100(17)-V-ST dated March 31, 1979 ?" 2. Facts lie in a narrow compass. The assessee (M/s. Rajesh Electricals, Indore) is a registered dealer carrying on business mainly of purchase and sale of centrifugal pumps and electric goods on wholesale basis. Regular books of accounts have been maintained and sales and purchases have been fully vouched. The rate of tax on centrifugal pumps has been reduced from 5 per cent to 3 per cent vide Notification No. 1100(17)-V-ST dated March 31, 1979. This notification was issued by the State Government under section 12 of the M.P. General Sales Tax Act 1958 (annexure "A"). This notification contains that agricultural implements operated with the aid of power are entitled to the benefit of the reduced rate of tax. The relevant item contains centrifugal pumps also The assessee claimed benefit of reduced rate of tax on centrifugal pumps sold by it. The concerning authority, however, rejected the claim on the ground that stated pumps sold by the assessee were not centrifugal pumps covered by the notification but were pumping sets, liable to tax at the enhanced rate of 5 per cent as is application to pumping sets (annexures "B/1" to "B/4" and "C"). The assessee then preferred first appeal before the Additional Appellate Deputy Commissioner of Sales Tax. The appeals were, however, rejected on March 30, 1983 (annexure "D"). Dissatisfied the assessee preferred second appeal before the Tribunal. The appeals were registered as 82-PBR/83 and 83-PER/83 relating to the period 1980-81 and 1981-82. The appeals were allowed in part (annexure "F"). The assessee then preferred first appeal before the Additional Appellate Deputy Commissioner of Sales Tax. The appeals were, however, rejected on March 30, 1983 (annexure "D"). Dissatisfied the assessee preferred second appeal before the Tribunal. The appeals were registered as 82-PBR/83 and 83-PER/83 relating to the period 1980-81 and 1981-82. The appeals were allowed in part (annexure "F"). It was held that monoblock pumping sets were covered by the expression centrifugal pumps and were liable to be subjected to the concessional rate of 3 per cent. It, however, held that coupled pumping sets are liable to be taxed at 5 per cent. The decision dissatisfied both the sides. The department filed two applications and the assessee also filed two applications seeking statement of case and reference of question. On these four applications, the Tribunal referred the aforesaid two questions of law. One on the applications of the department and the other on the applications of the assessee. 3. We have heard Shri S. Kulshrestha, leaned Additional Advocate-General for the applicant/department and Shri P. M. Choudhary, learned counsel for the non-applicant assessee. 4. The Tribunal took the view as under : "Thus the judicial consensus of the three High Courts is that a power driven centrifugal pump is an agricultural pump. As far as the monoblock pumping sets are concerned, it is clear that it will be taxed as a centrifugal pump under the notification dated March 31, 1979 at 3 per cent. As far as coupled sets are concerned, they are not a monoblock. The bills shown by the appellant show that despite the fact that one price was charged for every set with a separate motor number and a separate pump number. Here in the case of monoblock pumps the motor is an integral part of the pump, in the coupled sets it is not an integral part. Both of them can be used separately. Whereas the monoblock pump would be taxed at 3 per cent and the coupled pumping sets will be taxed at the rate of 5 per cent." 5. The Allahabad High Court in [1987] 65 STC 227 (Commissioner of Sales Tax v. Indian Turpentine & Rosin Co. Both of them can be used separately. Whereas the monoblock pump would be taxed at 3 per cent and the coupled pumping sets will be taxed at the rate of 5 per cent." 5. The Allahabad High Court in [1987] 65 STC 227 (Commissioner of Sales Tax v. Indian Turpentine & Rosin Co. Ltd.) held as under : "Held, dismissing the revision, that if a commodity was used for two different purposes, it was the use which would determine the nature of the commodity liable to be taxed, and that the Tribunal was justified in holding that 85 per cent of the vegetable turpentine oil produced by the respondent, sold to the aforesaid firm, fell under item 31 of the List of Notification No. 5785 dated 7th September, 1981, and was chargeable to sales tax at 4 per cent." 6. According to Webster's New World Dictionary, the meaning of "centrifugal" is as under : (i) Moving or tending to move away from centre; (ii) using or acting on by centrifugal forces; (iii) conveying away from a centre : efferent; (iv) a machine that uses or causes centrifugal movement." 7. The meaning of "centrifugal force" is "the force ending to pull a thing outward when it is rotating rapidly around a centre". "Centrifugal pumps" are of two types as popularly known in commercial transaction. Monoblock centrifugal pump is one marketable commodity and is sold as such as one unit in one block. The centrifugal pump and electric motor are attached with one common shaft and are inseparable ([1980] 46 STC 504 (P&H) [Paul Electric Company v. Assistant Excise and Taxation Commissioner (Inspection)]. In the above decision, the High Court placing reliance on the Supreme Court decision in case of Porritts & Spencer (Asia) Ltd. [1978] 42 STC 433, has held that a monoblock centrifugal pump is included in the words "centrifugal pump". Coupled pump sets are those in which the centrifugal is coupled with either electric motor or diesel engine. The question whether coupled pump sets are centrifugal pumps has been dealt with in the case of Sterling Machine Tools v. Commissioner of Sales Tax [1979] 43 STC 72 (All.). It is held that the pump attached to the diesel engine, in scientific phraseology, is called a centrifugal pump and not a water pump, although it can pump out water on being attached to a diesel engine or electric motor. It is held that the pump attached to the diesel engine, in scientific phraseology, is called a centrifugal pump and not a water pump, although it can pump out water on being attached to a diesel engine or electric motor. Centrifugal pumps become capable of pumping out only with the aid of diesel engine or an electric motor. 8. The assessee emphatically stated that it sold the coupled pumping sets with motor so as to be used as centrifugal pumps and did not sell the coupled pumping sets and motor separately. In view of this factual position, the counsel for the assessee urged, the Tribunal was not justified in holding that coupled pumping sets despite their sale as centrifugal pumps were not covered by the notification dated March 31, 1979. 9. It is in the area of legislative ambiguities, yet not receding, that courts have to fill gaps, clear doubts and mitigate hardship. In the words of Judge Learned Hand, spoken in Cabell v. Markhan (1945) 148 F 2d 737 at 739, we get enough light to locate correct path : "It is one of the surest indexes of a mature and developed jurisprudence....to remember that statutes always have some purpose or object to accomplish whose sympathetic and imaginative discovery is the surest guide to their meaning." 10. As per the aforesaid notification dated March 31, 1979, centrifugal pumps are required to be given benefit of reduced tax of 3 per cent. If sale of monoblock pumping sets is accepted by the Tribunal as governed by the notification it is little to understand as to why coupled pumping sets were not so accepted for concessional rate of tax. 11 Indisputably centrifugal pumps are covered by the notification providing for reduced tax of 3 per cent. The simple question for consideration was whether monoblock pumping sets and coupled pumping sets are covered by the description "centrifugal pumps" ? The assessee attempted to show that these pumping sets (monoblock and coupled) were demonstrably covered by the notification dated March 31, 1979. It is not clear from the record as to why coupled pumping sets were not treated as centrifugal pumps and if use is determining factor then it should have been ascertained from the account books and vouchers as to for what purpose the assessee effected the sales. It is not clear from the record as to why coupled pumping sets were not treated as centrifugal pumps and if use is determining factor then it should have been ascertained from the account books and vouchers as to for what purpose the assessee effected the sales. The question which depends on proof of facts is not properly a pure question of law. It would indeed be mixed question of fact and law. 12. In AIR 1936 PC 253 (Nazir Ahmad v. King Emperor), it is held as under : "The rule which applies is a different and not less well recognised rule, namely that where a power is given to do a certain thing in a certain way the thing must be done in that way or not at all. Other methods of performance are necessarily forbidden." 13. In the instant cases power is given to the taxing authorities to do a certain thing in a certain way. According to the provision of law, it is thus clear that the things should be done in that way alone. The taxing authorities were required to understand by cogent and convincing material as to whether or not the coupled pumping sets were centrifugal pumps within the meaning of the notification dated March 31, 1979. More so when the assessee was emphatic that it sold the entire sets to be used as centrifugal pumps and did not sell the pumps and motor separately so as to establish any disconnection between the two. 14. The question has been formulated in the facts and circumstances of the case. There is no serious dispute that monoblock pumping sea is liable to tax at the rate applicable to centrifugal pumps, i.e., at 3 per cent. As regards the coupled pumping sets, the logical conclusion is that the same shall be treated as centrifugal pumps so long as motor is not sold separately as distinct item and identity. 15. In the circumstances, we answer the questions as under : (a) Question No. 1 : As regards monoblock pumping sets, we hold that the Tribunal was justified in holding that the sale of monoblock pumping sets was liable to be taxed at the rate applicable to centrifugal pumps, i.e., 3 per cent. 15. In the circumstances, we answer the questions as under : (a) Question No. 1 : As regards monoblock pumping sets, we hold that the Tribunal was justified in holding that the sale of monoblock pumping sets was liable to be taxed at the rate applicable to centrifugal pumps, i.e., 3 per cent. We, therefore, answer this question in the affirmative, i.e., in favour of the assessee and against the department (b) Question No. 2 : As regards coupled pumping sets, we hold that the coupled pumping sets when sold along with motor, will be covered under the expression "centrifugal pumps" and thus by notification dated March 31, 1979 but shall not be so covered if couple pumps and motor are sold separately and not as centrifugal pumps. We, therefore, answer this question this in the negative, i.e., in favour of the assessee and against department if factually coupled sets and motor were sold as one common shaft as inseparable unit but in the affirmative, i.e., against the assessee and in favour of the department if coupled pumping sets and motor were sold separately as distinct unit with distinct identity so as not to operate as centrifugal pumps, for different purpose. 16. These reference applications are thus answered accordingly but with no order as to costs. 17. Copy of this common order shall be sent to the Tribunal under the seal and signature of the Registrar of this Court under section 44(5) of the aforesaid Act. 18. This order shall be retained in Misc. Civil Case No. 389 of 1986 and one copy each shall be placed in the record of connected cases for ready reference. Reference answered accordingly.