Judgment S. J. Mukhopadhaya, J. 1. This appeal relates to determination of principle of seniority. The appellants who were initially appointed in the Work charge Establishment, were subsequently merged and confirmed in the regular Cadre, in the Regular establishment of the respondent State. The question for determination is whether he period rendered by the appellants in the Work Charge Establishment against equivalent posts is to be counted for the purpose of determination of seniority in the Regular Establishment or not. 2. The appellants filed a writ petition C. WJ. C No.1223 of 1983 challenging one order dated 15th February, 1983. By the aforesaid order, it was directed to prepare a seniority list of assistant Research Officers. The earlier period rendered by the appellants in the work Charge Establishment against similar posts of Assistant Research officer was ordered to be ignored. The writ-petition aforesaid has been dismissed by the learned single Judge which was analogous with another writ-petition. Hence, the present appeal. 3. The brief facts of the case are as follows: under the respondent State in its water Resources (Irrigation) Department, there are two Establishments: namely, (1)Work Charge Establishment, and (2)Regular Establishment. While the posts in the Work Charge Establishment are in the regular scale of pay, like that of the regular Establishment, but such posts in the Work Charge Establishment are/were temporary posts. The appe|ants were initially appointed as research Assistants, on temporary basis in the Work Charge establishment of the Water Resources (Irrigation) Department. They were so appointed after following the procedure of appointment i. e. after advertisement, interview through the Selection Committee and on the basis of their position in the panel. The appellant No.1 was appointed in the work Charge Establishment as research assistant on 5th March 1965; appellant nos.2 and 3 on 29th August, 1965. According to the appellants, while the advertisement was issued for appointment to the post of Research Assistant, in the said advertisement, it was not mentioned that the appointments were made in the work charge Establishment of the department. However, when the appointment letters were issued to the appellants, therein it was mentioned that they have been appointed as research Assistant in the Work Charge establishment on temporary basis. To support their averment they have annexed copy of advertisement dated 22nd April, 1965. However, when the appointment letters were issued to the appellants, therein it was mentioned that they have been appointed as research Assistant in the Work Charge establishment on temporary basis. To support their averment they have annexed copy of advertisement dated 22nd April, 1965. It is to be taken into note that the post of research assistant has been redesignated as assistant Research officer. Admittedly, there are equivalent post of research assistant (now known as assistant Research Officer), with same scale of pay, qualification etc. in the regular establishment of the Department. The seniority of persons employed in the regular establishment used to be maintained separately in the year 1974, the cadre of all research assistants of different Departments, like - Irrigation department, R. V. P. Department were unified to a joint unified cadre, vide decision contained in letter No.1125 dated 27th July 1974. However, this unification of cadre of research assistants was with regard to the research assistant who were in the regular establishment. 4. So far as the appellants are concerned, they continued to function as research assistant in the Work Charge establishment and continued to receive their salary in the regular scale of pay with increments, as was due in each and every year. They were also allowed to cross EB but could not be made permanent because of the fact that the posts in the Work Charge establishment were temporary posts. 5. The respondent State took a policy decision in the year 1976, vide letter No.2742 dated 25th February, 1976. The following decision was taken: (i) The persons who were working in the Work Charge Establishment continuously for ten years, they should be confirmed in the regular establishment with effect from 1st April, 1975; (ii) For the aforesaid purpose, it was decided to transfer the post of Work charge Establishment and to make merge the same in the regular establishment and to make them permanent post with effect from 1st April, 1975. The effect of the order was that the posts which were continued for more than ten years in the Work Charge establishment, they stood merged with the equivalent cadre post in the regular establishment with effect from 1st April, 1975. The effect of the order was that the posts which were continued for more than ten years in the Work Charge establishment, they stood merged with the equivalent cadre post in the regular establishment with effect from 1st April, 1975. The incumbents who were holding such posts for more than ten years in the Work Charge Establishment, they were absorbed along with their post in the equivalent cadre of regular establishment with effect from 1st April 1975 and were made permanent from the said date, i. e.1st April 1975. Total 8 posts of research assistant of regular establishment with effect from 1st April 1975. Formal notification to that effect was issued with respect to the appellants, by subsequent orders. By one order No.602 dated 31st March 1976, appellant no.1 along with two other persons, was confirmed in the regular establishment as research assistant. By another order contained in letter No.2022 dated 22nd november, 1976, appellant Nos.2 and 3 were also absorbed in the regular establishment and confirmed as research assistant in the regular establishment. 6. Then the question came as to how the seniority list of research assistants in the regular establishment were to be prepared. At this stage it is stated that there was no separate rule relating to fixation of seniority with respect to research assistants. The guidelines were issued by the State Government from time to time for different Class-II and class-Ill employees, which became subsequently statutory rules. The example is 1934 rules and 1944 rules of seniority. I am not discussing the aforesaid Rules in view of the fact that the said seniority rule relates to determination of seniority vis-a-vis direct recruits and promotees and does not cover the matter relating to seniority in a situation like the present one i. e. where persons are inducted by way of absorption, along, with their post in a cadre. However, it is to be taken into note that a separate circular was earlier issued vide letter No.15784 dated 26th august 1972 for determination of seniority in general where in the expression-at the same time was made synonymous to the term-same transaction. However, it is to be taken into note that a separate circular was earlier issued vide letter No.15784 dated 26th august 1972 for determination of seniority in general where in the expression-at the same time was made synonymous to the term-same transaction. Further in paragraph 3 (v)of the said circular dated 26th August 1972, certain guidelines were laid down as to how seniority is to be fixed, if an incumbent of Work Charge Establishment is appointed to the regular service cadre in the regular establishment, it was mentioned that on appointment in the regular establishment, the erstwhile incumbent of Work Charge establishment should be treated to have been appointed afresh in the said regular establishment. The relevant paragraph 3 (v) of the Circular dated 26th August 1972 reads as follows: "3 (v): The incumbents of Work charge Establishment on their appointment to the regular service cadre will be treated as fresh recruits and they shall rank senior to the regular direct recruits cf the same transaction. " 7. At this stage it is to be taken into note that the aforesaid guideline relating to seniority made vide letter dated 26th August 1972 is a general guideline for all Departments and not a statutory rule. I will discuss the matter at the appropriate stage with respect to the circular dated 26th August, 1972, as the learned Single Judge has taken the same into account for deciding the present case. 8. As was taken into note that after merger of posts of research assistants which were available in the Work charge Establishment with the regular cadre post of regular establishment, of research assistants, the question arose as to how seniority of such incumbents was to be decided who were taken in the regular establishment by way of absorption. The respondent State by its resolution No.1056 dated 8th June 1977, which was issued from the then public Works Department (the controlling department of all Works Departments), decided that the period rendered by a person against an equivalent post of research assistant in the Work Charge Establishment will be counted for the purpose of seniority as research assistant in the Work Charge establishment, on their absorption. The resolution aforesaid dated 8th June 1977 was issued by the order of Governor of Bihar and it was published in the gazette. 9. The resolution aforesaid dated 8th June 1977 was issued by the order of Governor of Bihar and it was published in the gazette. 9. The aforesaid principle laid down by resolution dated 8th June 1977 was made applicable with regard to the research assistants of the Water Resources (Irrigation) Department. The principle laid down vide resolution dated 8th june 1977 was followed in the public works Department and after counting the period of service of research assistants tants in the Work Charge Establishment, the seniority list was prepared with respect to research assistants of public Works Department. Initially, tentative gradation lists were published with respect to the research assistants of water Resources (Irrigation) Department, but ultimately vide impugned letter No.977 dated 15th February 1983 when it was ordered to prepare seniority list of research assistants in the combined cadre of regular establishment, direction was given to follow the principle laid down in paragraph 3 (v)aforesaid of letter No.15784 dated 26th june, 1972 and not on the basis of resolution dated 8th June 1977. In effect, it was ordered to prepare seniority list of research assistants in the regular rstablishment of Water Resources (Irrigation) Department without counting the period of service rendered by the research assistants in the Work Charge establishment. 10. As stated above, the appellants challenged the aforesaid impugned letter No.977 dated 15th February, 1983 by filing writ-petition C. W. J. C. No.1223 of 1983, which has been dismissed by the learned Single Judge. The learned single Judge confirmed that the principle enumerated in paragraph 3 (v) of letter dated 26th August, 1972 will be applicable for determination of seniority of research assistants, like appellants, who were absorbed from the work Charge Establishment to the regular establishment, because of merger of their posts. 11. Now the following questions emerge for determination: (i) Whether, in the present case, the period of service rendered by the research assistants in the Work Charge Establishment, on merger of posts and on their absorption in the regular establishment, such earlier period rendered in the Work charge Establishment is to be counted for determination of seniority in the regular establishment. Now the following questions emerge for determination: (i) Whether, in the present case, the period of service rendered by the research assistants in the Work Charge Establishment, on merger of posts and on their absorption in the regular establishment, such earlier period rendered in the Work charge Establishment is to be counted for determination of seniority in the regular establishment. (ii) Whether for the purpose of determination of seniority, paragraph 3 (v) of letter dated 26th August, 1972 is applicable in the case of Research Assistants of water Resources (Irrigation) Department, and, (iii) Whether the resolution No.1056, dated 8th June, 1977 will prevail over the letter dated 26th August 1972 or not, for the purpose of determination of seniority of research assistants of the Water resources (Irrigation) Department. 12. According to the Counsel for the appellants, the earlier period rendered by the appellants as research assistant in the Work Charge Establishment is to be counted for determination of their seniority as research assistant in the regular establishment. It was contended that the appellants are not direct recruit to the cadre of research assistant in the regular establishment and thereby paragraph 3 (v) of letter, dated 26th August, 1972 is not applicable in their case. It was further submitted that the appellants having been appointed on regular basis, after following all the procedures of regular establishment, though their initial appointments were made in the Work charge Establishment, on their absorption in the regular establishment, such period cannot be ignored for the purpose of determination of their seniority. 13. In fact, the main argument as was advanced by the Counsel for the appellants before the learned Single judge, as also before this Bench, was that the earlier period rendered by the appellants in the Work Charge Establishment should be treated as continuous officiation and on that principle, the same should be counted for the purpose of determination of senior in the regular establishment. 14. The learned Advocate-General appeared on behalf of the respondent state and its authorities. According to him, the appointment of appellants having been made in the Work Charge establishment, the same should be treated as ad hoc appointment. It was contended that their initial appointment in the Work Charge Establishment being ad hoc, in nature, the same cannot be counted for the purpose of determination of seniority as research assistant in the regular establishment. According to him, the appointment of appellants having been made in the Work Charge establishment, the same should be treated as ad hoc appointment. It was contended that their initial appointment in the Work Charge Establishment being ad hoc, in nature, the same cannot be counted for the purpose of determination of seniority as research assistant in the regular establishment. He relied on the decision of the supreme Court in the case of S. K. Shaha V/s. Prem Prakash Agrawal and others ( AIR 1994 SC 745 ); in the case of g. Gangarasmiah V/s. A. Narayan ashmy and others ( AIR 1994 SC 838 ) and in the case of Excise Commissioner, karnataka and another V/s. Shreekanta ( AIR 1993 SC 1564 ). 15. At this stage it is to be taken into note that certain persons were directly recruited as research assistant in the regular establishment, in between the initial appointment of appellants in the Work Charge Establishment and their regular absorption in the regular establishment. They have intervened in the present Letters Patent Appeal. By an order dated 26th Aug. , 1991, a Bench of this Court allowed their intervention. According to the Counsel for the intervenor respondents, seniority of incumbents of a cadre is to be determined on the basis of their entry in the said particular cadre. It was contended that the date on which the appellants were taken, in the regular establishment cadre, such date is to be treated as their date of appointment in the regular establishment cadre and the seniority is to be determined on that basis. Further, according to him, there being a guideline issued by the State Government, vide circular, dated 26th August, 1972, paragraph 3 (v) of which is specific with regard to the incumbents appointed in the regular establishment from the Work Charge Establishment, the appellants are guided by the same which has been rightly followed by the respondent State, vide, their impugned letter No.977 dated 15th February, 1983. It was submitted by the Counsel for the intervenor-respondents that the learned Single Judge rightly disallowed the period rendered by the appellants in the Work Charge Establishment for the purpose of determination of seniority in the regular establishment and thereby the appeal is fit to be dismissed. It was submitted by the Counsel for the intervenor-respondents that the learned Single Judge rightly disallowed the period rendered by the appellants in the Work Charge Establishment for the purpose of determination of seniority in the regular establishment and thereby the appeal is fit to be dismissed. He further tried to impress the Court that the appointments of appellants were not substantive in nature and till they were confirmed, they cannot be treated to have been appointed in the cadre. In this connection he relied on a Division bench decision of this Court in the case of Gaya Prasad Pandey and another V/s. The State of Bihar and others (AIR 1969 pat.311 ). He has also placed reliance on the decision of the Supreme Court for the purpose of definition ofsubstantive appointment, in the case of Baleshwar dass and others V/s. State of U. P. and others ( AIR 1981 SC 41 ). Further reliance was placed by him with respect to the principle relating to determination of seniority, on a decision of this Court, in the case of Manmohan Prasad V/s. Food corpn of India (1984 PUR 30) and the decision of the Supreme Court in the case of Kalyani Dayal and Ors. V/s. Union of india and Ors ( 1980 (3) SCC 245 ). 16. According to me, the general principle relating to determination of seniority is not applicable in the present case. So far as the entry of appellants in the regular establishment is concerned, it was made by way of absorption. It will be evident from the letter No.2742 dated 25th February 1976 that the respondent State decided to merge the post of research assistant of the Work charge Establishment with the regular cadre post of regular establishment. The effect is that the strength of the cadre of research assistant in the regular establishment increased because of such merger and appellants were inducted in regular establishment by way of absorption. This source of appointment of appellants in the regular establishment by way of absorption is neither a direct recruit nor it is a matter of promotion. The effect is that the strength of the cadre of research assistant in the regular establishment increased because of such merger and appellants were inducted in regular establishment by way of absorption. This source of appointment of appellants in the regular establishment by way of absorption is neither a direct recruit nor it is a matter of promotion. Therefore, so far as the guideline issued by the respondent State vide their letter No.15784 dated 26th august, 1972 is concerned, particularly paragraph 3 (v) therein, the same cannot be made applicable in the present case for the following reasons: " (a) The letter dated 26th August 1972 is not a statutory rule and has already been doubted by a Full Bench of this Court In the case of Bishumdeo mahto V/s. The State of Bihar and others (1962 BBCJ 45) and the definition of at the same time was held to be not synonymous with the definition of at the same transaction. The relevant paragraph reads as follows: 28 :. . During the course of argument, our attention was drawn to Government notification being memo No.5805 dated 27.4.1966 which seeks to bring about certain changes in the rules of 1934 and 1944. It was not shown during the course of argument that the notification had force of a rule under Article 309 of the constitution. I entertain grave doubts whether this notification can bring about changes in the rules of 1934 and 1944 which are, as already held, rules under article 309 of the Constitution. Our attention was also drawn to Government circular no.3/ri-106/72-P-15784, dated 26.8.1972 which is noted to paragraph 3, states that the expression "at the same time" means in the same transaction. This notification has also not been shown during the course of argument, to have force of rule under Article 309 of the Constitution. The government would, therefore, be well advised to bring about the desired changes by framing proper rules under Article 309 of the Constitution and not by merely issuing department circulars. It is well settled that where the rules under Article 309 of the Constitution are silent, the departmental circular may supplement them. But where there is any change brought about by the circular which is in contradiction to the rules, the circular cannot prevail over the rules. The executive instruction may supplement but not supplant the rules. It is well settled that where the rules under Article 309 of the Constitution are silent, the departmental circular may supplement them. But where there is any change brought about by the circular which is in contradiction to the rules, the circular cannot prevail over the rules. The executive instruction may supplement but not supplant the rules. " (b) Apart from the same, paragraph 3 (v) stipulates as to how the seniority is to be determined, if a person is appointed from the Work Charge Establishment to the regular establishment. In the present case, the appellants have not been appointed by general procedure in the regular establishment. They have been inducted in the regular establishment by way of absorption because of the merger of their posts in the regular establishment. Paragraph 3 (v) of the letter dated 26th august, 1972 does not cover such cases. " (c) The resolution No.1056, dated 8th June, 1977 issued from the Public works Department, which is nodal Department of all the Works Departments, including the Water Resources (Irrigation)Department will prevail over letter dated 26th August 1972 for two reasons; (I) Because the resolution dated 8th june, 1977 has been issued by the order of the Governor of Bihar, whereas the other one is merely a letter issued by one of the officials by. the order of the Government; and (ii) The resolution dated 8th June 1977 is the specific guideline relating to seniority of research assistants, who have been merged from the Work Charge establishment to the regular establishment. Such specific guideline being there, the same has got overriding effect on general guideline, like the letter dated 26th August, 1972, and (d) The State Government cannot make applicable two different guidelines relating to seniority with respect to similarly situated, persons having same designation and Same scale of pay in two departments. The research assistants of the Public Works Department will be guided by resolution dated 8th June, 1977 and the Research Assistants of Water resources (Irrigation) Department will be guided by letter dated 26th August, 1972-this argument cannot be accepted, otherwise the same will be violative of articles 14 and 16 of the Constitution of india. " 17. The research assistants of the Public Works Department will be guided by resolution dated 8th June, 1977 and the Research Assistants of Water resources (Irrigation) Department will be guided by letter dated 26th August, 1972-this argument cannot be accepted, otherwise the same will be violative of articles 14 and 16 of the Constitution of india. " 17. Apart from the same, the supreme Court in the case of K. Madhvan and another V/s. Union of India and others ( AIR 1987 SC 2291 ) in a similar case of absorption from one cadre to another cadre, ordered to count the seniority of earlier period for the purpose of determination of seniority in the cadre where the incumbent was absorbed, as both the posts were equivalent. The aforesaid principle laid down by the Supreme Court is squarely applicable in the case of research assistants, like the appellants, who have been merged and absorbed in the regular establishment. 18. For the reasons stated above, I hold that the impugned letter No.977 dated 15th February, 1983 as illegal. The judgment delivered by the learned single Judge does not lay down the correct principle of law. I further hold that the appellants are entitled for seniority as research assistant in the regular establishment of Water Resources (Irrigation) Department, counting the service rendered by them as research assistant in the Work Charge Establishment. The respondents are directed to provide the appellants seniority in the regular establishment on the basis of their date of appointment as research assistant in the work Charge Establishment and to provide them with consequential benefit of the same, including promotion and other benefits, if any. 19. In the result, the impugned judgment of the learned Single Judge, so far it relates to C. WJ. C. No.1223 of 1983, is set aside. The Letters Patent appeal is allowed and in effect writ petition C. WJ. C. No.1223 of 1983 stands allowed. In the facts and circumstances of the case, there will be no order as to costs. Order Accordingly.