needs no cement or steel nor any mechanical aids, is a factor which makes the system very appealing particularly in developing nations and communities.

It should however be noted that oxidation pond is not a panacea of all sewage treatment problems but certain features make it especially applicable under a wide variety of conditions. Because of the relatively large area required, the greatest application would be to small and medium size communities where the land is readily available.

The Institute is also conducting studies on large reservoirs to suppress the evaporation using_monolayer technique with cetyl alcohol. Evaporation control technique is of relatively recent origin. A chemical known as cetyl alcohol is spread on the lake in the form of a monomolecular film on the water surface. This film is effective in reducing the evaporation losses to a great extent. It has been observed that the film can suppress the evaporation losses upto fifty per cent and in centain cases even more, depending on the meteorological conditions prevailing on the site. However, 15 to 30 per cent reduction in evaporation losses is a common experience in India as well as in other countries under the field conditions.

In order to help the soldiers on the front, the Institute had been studying to develop (1) a mobile filter, (2) demineralising unit, (c) a water purifying cartridge, (d) an efficient and bandy water testing kit, and (e) an efficient method for disposal of faecal matter above the snow line. Studies on relative efficiencies of chlorine and iodine for disinfecting small quantities of water are also in progress.

Many water supply schemes are referred to the Institute for technical scrutiny. Several such schemes are scrutinised by the Institute and suggestions for economic alternatives are given. Rural sanitation problems like design of gobar gas plants for lighting and supplying domestic fuel, wheelbarrows for transport of night soil, design of cheap sanitary ware for providing modern conveniences for villagers are being tackled by the environmental sanitation division.

The Instrumentation Division helps the

Institute scientists in the maintenance and servicing of the valuable instruments in the laboratories. Trials are being made to fabricate simple instruments which are useful for determining and recording continuously dissolved oxygen, biochemical oxygen demand and certain other parameters.

W. H. O. and T. C. M. (now U. S. A. I. D.) are taking keen interest in the activities of the Institute and it is hoped that this Institute will develop into a research and training centre in public health engineering for South-East Asian countries. The W. H. O. has given a grant of Rs. 25 lakhs for equipment and apparatus and under the project "assistance to the Institute" has agreed to provide short-term consultants in various fields of research in public health engineering.

Many eminent scientists are working at the Institute, Mr. R. S. Mehta, Director of the Institute, has specialised in the field of public health engineering for more than 30 years. He is also a member of the Environmental Hygiene and Sanitation Expert group of the Indian Council of Medical Research and on several committees dealing with Sanitary Engineering problems.

PVC Pipes And Guttering

pipes made from PVC, reported on in the A new range of gutters and downfall BBC World Service 'New Ideas' programme, is likely to be attractive to amateur as well as professional builders.

"One of its big advantages," said reporter Terry Doughty, "is that the fitting is so easy. Brackets and outlets are secured by a single screw. Once they are fixed, all you do is cut the guttering itself to the right length, then literally snap it into place. With the fall-pipes the procedure is the same, except that they can be screwed to the wall at two points if need be. As for costs, the average job would come out at much the same cost as for ironware guttering. But the plastic really has a long life, and needs no paint to preserve it."

The makers are J. W. Roberts Limited, of Horwich, Bolton, Lancashire.

City Transport

The highly congested city of Calcuttaperhaps the highest in India, is day by day turning to be a headache to the Civic authorities and the Government. Besides all the problems of feeding the millions, their sanitary condition etc., the problem of transport system, which is far below the requirement, has tended to be a crucial one. In this perspective, the urgent need for a Circular Railway is to be analysed.

The Background

The basic idea of a Circular Railway is not a new one. As early as in 1914, Mr. Merz and McLellan advocated the need for electrification of the Suburban Railway bringing it to Dalhousie Square.

The concept of a Circular Railway in the present form was first initiated by a Committee known as the Terminal Facility Committee presided over by Sri Padmaji Ginwalla in 1947. The recommendations of this Committee, with certain modifications being endorsed by a Committee headed by Sri S. N. Roy and appointed by the Government of India in 1953, were accepted and the Report on the electrification of Eastern Railway in 1960 also proposed to take up the work on Circular Railway in Phase III of the scheme.

now

During the last two years, the Calcutta Metropolitan Planning Organisation has been investigating the proposals. The existing shape of the proposed Circular Railway is to cover the route started from Dum Dum via Chitpur Yard, Hastings, Kidderpore Dock, Majerhat Junction and then the return-route along Kalighat, Bullygunge, Park Circus, Beliaghata to Dum Dum.

Why Needed Urgently

The population of the Calcutta Metropolitan Area, increased enormously after the partition due to the influx of refugees, is estimated now about 6.5 million which is expected to rise to more than 11 million within next 20 years.

Obviously, the tremendous growth of population has put an excessive pressure on

the transport system. During the last 10 years Suburban passengers have increased by more than 100 per cent. But the commuterstrain cannot bring the passengers to their ultimate destination. The centre of business activity in Calcutta is in the vicinity of Dalhousie Square and Burra-Bazar areas but the passengers are detrained at Howrah and Sealdah Terminal both lying far away from the most of the said area.

This induces two big problems. There is a considerable delay and loss of time in reaching the Central business area from the railway stations. Secondly, the congestion in roads leading from the terminal causing thereby aweful hardship to the non-officegoers. The city public transport system in its desparate attempt to cope with the growing demand is also strained beyond capacity. Two Principal Objectives

In view of this, the need for a Circular Railway is appeared to be an imperative. It has two principal objectives before it. The first is to bring the daily passengers from the neighbouring townships and colonies to the Central core area. This would largely eliminate the need of any other form of transport between the railway terminal and the core area. From a station in Strand Road, the core area will be at a stone's throw. The second objective is to provide a rapid transit communication along the periphery between the North and South of the city. This means that a considerable volume of the North-South movements would be performed by Circular Railway and this would gradually relieve the congestion in transport on the intra-city communication system.

Immense Improvement of Traffic

Traffic around the central core area, a recent investigation shows, is the maximum and the total number of transit passengers entering the core area in an average week day is 7,37,915. Of this, 1,60,441 come from the East, 1,66,032 come from the West, 2,65,384 come from the North and 1,46,058