Not long after Jane and I got married, David followed suit by marrying Maria Torres, a biochemist who had come from Portugal to work in Colchester where David now worked in the University Mathematics Department. Then the first grandchildren started to arrive: Jane and I produced four between 1973 and 1976, starting with the only girl, Jane's daughter Kate, nicely timed to coincide with Reinet's retirement. John was filled with pride at each arrival for he saw his grandchildren as the perpetuation of a dynasty; knowing that his own genes had been handed down to a new generation gave him a great sense of fulfilment. He stood back while others fluttered and fussed round the children as small babies but as they grew up he was able to contribute by making a number of solid wooden toys for them. Reinet helped in the design and final painting of these and together they produced toys that will easily last several generations. A residue of shyness meant that he would not impose himself on the children any more than he would on anyone else but was delighted when they approached him. His pride in the children took the form of an intense interest in their development, especially of mental abilities, and he suggested to me that I might write up the story of my children's lives regularly; he said he would prefer this as a Christmas present each year to an endless succession of handkerchiefs. He so obviously enjoyed reading the instalments that David took up the habit when his two boys arrived a few years later.Kate seemed unhealthy from the start. She needed antibiotics repeatedly for ear infections, was small for her age and seemed weak and easily tired but Jane found it impossible to convince her doctor that there was anything wrong with the child. One evening, when Kate was two years old, John and Reinet brought up their worries about Kate in a conversation with Mike Chamberlain. Mike said that it sounded as if Kate had one of the malabsorbtion syndromes such as coeliac disease (an inability to digest wheat flour). Such a strong suggestion took Jane back to her doctor with increased confidence and Kate was admitted to hospital for a series of unpleasant tests. These tests revealed a condition far worse than coeliac disease, cystic fibrosis, for which there was no known cure, only palliative treatments. After this diagnosis, John made his usual attempt to find out as many facts as possible about the problem. When he discovered one of the leading experts, Professor Charlotte Anderson, to be working at the Birmingham Children's Hospital where Kate's case had been referred, he went to see her. He learnt that the effects of the disease on the lungs and digestive system were due to faults in the basic transport mechanisms for water from cells into certain of their secretions. He came away without the looked-for cause for optimism: research was at such an early stage that little was expected from it within the near future. Professor Anderson suggested that the only way that he could help was to support the Cystic Fibrosis Research Trust in its collection of funds for research. Reinet took up this suggestion and joined the Trust. It did not take her long to become Secretary of her local branch, which she proceeded to run with great success for eight years, boosting takings and providing support and information for countless families. At the same time she threw herself into providing practical support and encouragement for Jane. Professor Anderson's hopes for results from research into the disease were well-founded and the treatments for children with cystic fibrosis were constantly developed and refined throughout Kate's childhood and for a lot of the time she was kept reasonably well, albeit with daily uncomfortable and time-consuming treatment. For a time it almost seemed as if with every year of Kate's life, the average age at which sufferers died was increased by a year or two.
The 1970's brought plenty of opportunities for interesting travel. In 1971, John went with Mike Chamberlain and his wife to the Scientific Assembly of the World Federation of Nuclear Medicine and Biology at Los Angeles. John was disappointed not to see the famous smog but the representative of the City Council who welcomed them had a retort ready: "We don't like it either; we like to be able to see what we are breathing." John gave a short paper on in vivo activation analysis and then took an afternoon off to visit Disneyland. He had expected the theme park to be thoroughly corny, but in fact came away very impressed by a spectacle that was the best of its kind.
A year later he was back in the United States to give a talk on dating, meeting Henry Irwin again at Pullman in Washington State. On this trip he had a day of plant hunting and photography on a grassy hillside above Snake River. He had been taught to recognise poison ivy and curiosity led him to touch the edge of a leaf with the back of a hand. He found that it began where British stinging nettles leave off and was glad that he had used only a small area of his hand for the experiment. Ten minutes later he was stung by a scorpion. This time it was the scorpion's idea rather than his, but nevertheless the experience gave him the opportunity to compare it with a wasp's sting. A good deal worse, he decided, but not as bad as he had expected it to be from the accounts of others. His hand swelled up, as if in protest at his callous attitude.
In 1974 John and Reinet went together to the United States and Canada, first to visit Henry Irwin and his wife in Pullman, and then to London, Ontario to visit Mike and Barbara Chamberlain and their family who had moved there two years previously. John was booked to give some lectures on medical physics in the hospital where Mike worked. One day while he was there, a message was telephoned through to say that Reinet had had an accident. He was taken to her in another part of the same hospital to find that she had a key embedded in her knee.
So how had this happened? Reinet had gone with Barbara and her mother-in-law to a shopping centre. While her two hostesses were in a supermarket, Reinet had hurried off to try to find a present for the Chamberlains' son Tom whose birthday it was the next day. Reinet had always had a tendency to charge forward when in a hurry and doing just this, she tripped and fell onto her handbag. As she tried to sort herself out, she couldn't understand why her handbag appeared stuck to her knee until she discovered that her car ignition key had come through the leather and had, in effect, stapled the bag to her. A surgical operation was needed to remove it from her tibia.
John could not recall when asked whether they had any medical insurance. Of course they had; Reinet had organised perfectly adequate cover. He was very worried, wondering if Reinet would ever walk naturally, upsetting himself with the idea that they might never climb hills together again and the Chamberlains were struck with the tender concern he showed for her. They in their turn moved their whole household around to offer a more comfortable room for Reinet's convalescence. However, Reinet was mobile again sooner than they all expected, although the stitches were uncomfortable until she had them removed back in England.
In 1975, a scientific conference was held in Iraq by two Iraqis who had been students in Birmingham and John was invited to give the opening paper. After he had discharged this duty, he indulged himself in travel and sightseeing. A feature of this visit, which was now common in his forays to various parts of the world, was the high standard of hospitality offered to him by people who had been his students but were now developing their own successful careers in nuclear or medical physics.
Even after he turned 60 John was still tremendously busy, keeping research projects going while travelling both within Britain and abroad. Spare moments away from home were spent flower hunting and the slide collection now covered all but a very few of the British species. Free time in the evenings was used to catch up on reading journals or on mounting slides. John had never wanted his transparencies mounted in the usual flimsy paper or plastic holders but liked to use glass covers which he bought in their hundreds. Reinet called this job of taping transparencies into pairs of glass covers John's knitting as he would often carry on with it while talking to visitors.
Constant activity was no problem for John, but worry was: most of his research projects depended upon grants and for some years obtaining these had not been much of a problem. In 1974 he confidently put in for a further Medical Research Council (MRC) grant but nothing happened for some time and then his application was turned down. John was badly rattled by this, for it was needed not only for new equipment but to pay one of his best people. He was in a state of worry for four months until he managed to find out that his application had got into the wrong pigeonhole at the MRC office and so was appraised by the wrong committee, which had then dismissed it as inappropriate. Once this was sorted out, the right committee was not meeting again for some time, but at last the grant was confirmed. Other administrative pressures continued and there was often something to worry about especially when lack of time, or his own natural tendency to procrastinate, made him leave something important until after the last moment. At the same time, in the early seventies there was a massive move to take up jogging as a way of improving health, and, wondering if he was getting enough exercise, John decided to try this too. It did not occur to him to let himself work gradually up to a reasonable length of run just because he was sixty-three. He started to get chest pains and after trying to ignore them for a short time, he became increasingly worried. Sitting up in bed at night reading a medical dictionary, he decided that he had a heart problem and took himself to see his doctor. He was admitted to the Queen Elizabeth Hospital where this was confirmed. He was told that rest would give time to allow anastamoses to develop to bypass the blocked artery which was causing the trouble and he could gradually get back to full normal activity. A clear diagnosis with instructions as to how to effect a cure was exactly what John wanted to hear. He guided himself back to health by gradually increasing his physical activity over the following year and in addition he started to restrict his diet to keep his weight down, realising that in future he must treat his heart with respect. As he had been promised, by the next year John was fully recovered but any worries about heart problems had to be forgotten while his life became more hectic than ever with the Windscale Inquiry.
During the 1960's a left wing group and some CND members had founded the British Society for Responsibility in Science, motivated by the desire to produce technically accurate information on nuclear matters and John had been a member from the start. Good information was needed as much to stop other CND members making harmfully inaccurate statements about nuclear power as to refute the scurrilous statements of its opponents. In 1970 British Nuclear Fuels wanted to build a large new plant at Windscale (later Sellafield) to process spent fuels from the modern Advanced Gas-Cooled Reactors but before they could do this, they needed the approval of the Cumbrian County Council. The Council in turn approached the Society for advice. John and Dr Eric Burhop were invited by the Committee to investigate the proposals and suggest recommendations. John studied the wastes from the existing plant and calculated that the new plant would give one possible extra death per year of operation. Reporting to the Cumbria County Council, John pointed out that more deaths than this would of course occur, the conventional risks, to building workers for example, being far higher. The Council accepted this and gave the go-ahead for the plant.
There was, however, a lot of public opposition to the plant, and the Government set up an inquiry, under the inspectorship of the Honourable Mr Justice Parker, which took place in the summer of 1977 and was known as the Windscale Inquiry. Cumbria County Council had two legal representatives, Mr Glidewell, QC and a junior. John was taken on to advise them on technical matters.
The hearing was held in the Court House in Whitehaven. John found all the hotels in Whitehaven to be full so he stayed at a small hotel at Cockermouth from Sunday night to Friday morning each week and drove the seven miles to Whitehaven every morning, not infrequently overtaking a large tanker of liquid sulphur, which he saw as a far greater hazard than British Nuclear Fuels Limited. He spent his Saturdays and Sundays in Birmingham, mostly down at the University catching up with the most pressing paperwork.
Much of his time at the inquiry was spent listening to the evidence being given, looking out for incorrect statements. Each evening he would go round to the hotel in which Glidewell and his junior were staying and brief them on errors and misunderstandings in the day's submissions by the opposition. Sometimes John would need data that he didn't carry in his head and then Reinet acted as his research assistant. John would telephone her as soon as the court closed for the day, and, if possible, she would hunt up the necessary facts and have them ready for his telephone call to her before the court opened the next morning. John and Reinet owned a substantial number of reference books by this time, but in some cases a question could not be answered from these and Reinet might take a whole day researching a problem in the University library, a challenge that she thoroughly enjoyed.
In the latter half of the hearing John had a chance to give evidence himself. The weekend before this was scheduled however, he had gone down to Birmingham as usual, but had taken his respectable suit with him in order to go with Reinet, her nephew Michael and his wife to see a play at Stratford, a type of outing which John always enjoyed tremendously. Needless to say, the suit had got left behind in Birmingham as John had got into the habit of expecting it to be at Cockermouth and hadn't thought about packing it. Feeling that an open-necked shirt and flannel trousers were unsuitable for a court appearance, he rushed round to a shop in Whitehaven to buy a new jacket, choosing a light summer one, and a tie to match. Next day some parts of the press carried the remark that he looked like a CND member of the opposition and later a piece in New Scientist referred to his 'ice-cream jacket'.
John, however, was comfortable and felt quite smart enough. In his submission, he gave an explanation of the ways the new plant would differ from the old and then discussed the ways in which legal limits for exposure of workers in the field of nuclear applications are set. This was such that one in fifty workers who stayed in the industry for forty years might expect to die of cancer, which was about the same as the average risk of death from all forms of accident. But, he said, these legal limits were rarely even approached, making the real risk much lower. Then he dealt in detail with the possible risks due to transport, the processes themselves, disposal of waste and many possible types of accident; he pointed out that some deaths have to be expected, as with any activity, but for each part of the nuclear process he had calculated these, to his own satisfaction, to be very few.
One of the general worries aired in public about the plant was the possibility of radioactive materials getting into the food chain and being concentrated in the higher parts of it. John's calculations told him that deaths through eating fish after the new plant came into operation would be substantially less than one person per year. His report of his investigations in this area led to a slightly lighter moment within his evidence. He had got two members of the Friends of the Earth to obtain some samples of fish for him and they came up with eight plaice bought from a local fishmonger and a brill and a flounder caught specially for him from the Ravenglass Estuary. He had measured the amounts of Caesium-137 in them finding that that the most was in the brill and just sufficient for the next test he planned: "... I ate with much enjoyment the eatable parts of the brill, beautifully fried by my wife in a minimum quantity of fat." Colleagues then measured his whole-body content of caesium-137, finding a tiny increase exactly as expected and measured it again three days later when the activity was found to be unchanged. The measurements were continued over the next two and a half months, during which the activity halved. All John had shown was that all the caesium-137 which was eaten was absorbed into the body, but that it was then slowly lost. He didn't think the 0.0006 microcuries-1- he had absorbed dangerous. These experiments on himself were pounced upon by the journalists who had looked profoundly bored during most of the inquiry. One reporter arrived at the Fremlins' house to photograph Reinet frying a fish and she responded by getting 
one out of the freezer, temporarily, to load into the frying pan. He asked what they were going to do with the rest of the fish. "Eat them," said Reinet.The inquiry dragged on for seventy-seven days. As it went on into the autumn, John found that various engagements he had accepted before he realised it would go on for so long now needed attention. To keep these he had to drive all over the country for meetings in between court sessions and, perhaps for the first time in his life, he became very tired. When it was all over at last, the fees turned out to be useful but not in the conventional way: he didn't think he needed so much money personally and had it paid into research funds.
A year or two after the inquiry ended, one of the television channels screened a documentary of the event. It was amusing to see someone attempting to act my own father, copying his tendency to smile in a slightly embarrassed way at a point when a smile wasn't really necessary together with his habit of rubbing his nose when thinking!
In the summer of 1977 when John was approaching 65 he was asked whether he would retire or stay on for two more years, which, being a professor, he was entitled to do. This was at the time when he was rather tired after the Windscale Inquiry, but he was still very involved with several lines of research that he wanted carried on. Reinet suggested he ask to work half time, which the Vice Chancellor duly accepted. A few months later he got a telephone call from a worried head of the finance department who said that he had spent a great deal of time studying the proposition and could see no way of paying John for exactly half time. So would he consider working two thirds time? John's energy was already returning, so he happily agreed to this solution which in theory meant about a three day week, but, once the regime had started, he could quite often be found working a bit more when something interesting was going on.
Reinet was much more aware than John of their increasing ages and wanted them to look at the way they were going to live during their retirement. At home for more of the day, she was feeling the cold in the winter, but felt that installing central heating would be prohibitively expensive in such a large, old house. There were also several substantial maintenance jobs that would have to be done soon, not to mention the fact that a generously built six-bedroomed house was very big for two people. By 1978, Reinet was beginning to favour moving to something smaller. Looking ahead somewhat pessimistically she also wanted to dispense with stairs. John was not too sure about her reasoning: three thousand pounds for central heating seemed to him more a case for writing a cheque than for moving house, but as Reinet took on the task of house-hunting he went along with her suggestions. Eventually Reinet found the perfect answer in 46 Vernon Road at the other side of Edgbaston. A converted bungalow, there was spacious accommodation for the two of them on the ground floor and three small rooms upstairs which they could use for storage and for putting up visiting families with children. There was a large garden on which Reinet was to work very hard, producing an almost year-round riot of colour.
It was nearly three miles from the University, but John soon found that to walk there did him good. For all his reservations, he soon settled down, turned one room into a superb workshop and became convinced that it had been the right thing to do and had been done at the right time. They found straight away that they had the additional benefit of friendly, helpful neighbours, which had never been the case at Richmond Hill Road.