changed in the process during the past few weeks. He replied that nothing had changed; everything was exactly as before. My colleague noticed an empty, rusty bucket next to one of the vats and asked what it was. The foreman replied, ‘That is the old bucket from which we add the hydrogen peroxide to clear thegelatine at the final stage of cooking. As you can see it rusted away, so we bought a new one last week. Here it is.’ Light began to dawn. We knew that the lack of sulphide could have come from an excess of oxidant and here the new bucket was visibly larger than the old one. We soon solved the firm’s problem when we found that the new bucket was twice the volume of the old one. This small experience made real for me the academic fact that volume increases as the cube of the linear dimensions. The foreman buying the new bucket thought that an increase of one-quarter in diameter and depth was of small consequence. Universities can rarely supply golden experiences such as this.
My most vivid memory of apprenticeship days was the preparation of several hundred grams of the dye pigment carmine. The recipe was hand-written in an exercise book emblazoned with stains of the dyer’s craft. Take one hundred-weight of dried cochineal beetles, it said. Boil them in the copper with five gallons of ten-per-cent acetic acid. There was the 112-pound sack of beetles and the jars of acetic acid and in front of me was the copper. It looked just like the pictures I had seen of equipment in an alchemist’s laboratory. A semicircular stone parapet supported the large copper vat. A large wooden lid closed the top of the vat and heat came from a gas burner beneath it. The instructions said to bring the acid to a boil and then adjust the gas so that it slowly simmered. This I did, and then began to ladle in the beetles until they were all in the copper. The beetles cooked for four hours while a strange vinegary and musty odour filled the outhouse. I decanted the dark red-brown liquor from the beetle stew through a strainer into a set of jars. The next step was to add alum solution. Then, while stirring the mixture, to add ammonia. I watched the carmine lake precipitate. The last and most rewarding step was to filter the suspension of lake through a foot diameter filter paper held in a large porcelain funnel. I washed the powder several times and then put it in a vacuum desiccator to dry. At this final stage, it was a pure red colour so intense that it seemed to draw the sense of colour out through my eyes from my brain. What a joy to participate in the transmutation of dried beetles into immaculate carmine. I felt more like the sorcerer’s apprentice than merely Humphrey Murray’s junior technician.
A more down-to-earth business experience was the discovery that the firm profited by buying kilogram cartons of dye from ICI and packaging it in one-gram bottles. They then sold this back to their customers, which included other ICI departments, for as much as thekilogram cost. I stayed with the firm until July 1939. Humphrey Murray was by then, I think, fed up with my unbridled curiosity and chose to transfer me to work with one of their customers, the blueprint manufacturers, Norton and Gregory. I had an extraordinary sense of fulfilment as I worked out my apprenticeship as a scientist. I am full of gratitude to Humphrey Murray and to Tyrell, and my friends of that extraordinary firm.
In the spring of 1939, the students at Birkbeck and other evening-class colleges in London received a rude shock. The government announced its intention to conscript all fit young men for military service. Full-time students would be exempt but not part-time students like those at evening classes. My fellow students at Birkbeck shared my view that this was monstrously unfair. Here were we working both in the daytime and at night, the most diligent of students. How dare they penalize us? The political blood in my veins began to boil and I drew up a petition
My most vivid memory of apprenticeship days was the preparation of several hundred grams of the dye pigment carmine. The recipe was hand-written in an exercise book emblazoned with stains of the dyer’s craft. Take one hundred-weight of dried cochineal beetles, it said. Boil them in the copper with five gallons of ten-per-cent acetic acid. There was the 112-pound sack of beetles and the jars of acetic acid and in front of me was the copper. It looked just like the pictures I had seen of equipment in an alchemist’s laboratory. A semicircular stone parapet supported the large copper vat. A large wooden lid closed the top of the vat and heat came from a gas burner beneath it. The instructions said to bring the acid to a boil and then adjust the gas so that it slowly simmered. This I did, and then began to ladle in the beetles until they were all in the copper. The beetles cooked for four hours while a strange vinegary and musty odour filled the outhouse. I decanted the dark red-brown liquor from the beetle stew through a strainer into a set of jars. The next step was to add alum solution. Then, while stirring the mixture, to add ammonia. I watched the carmine lake precipitate. The last and most rewarding step was to filter the suspension of lake through a foot diameter filter paper held in a large porcelain funnel. I washed the powder several times and then put it in a vacuum desiccator to dry. At this final stage, it was a pure red colour so intense that it seemed to draw the sense of colour out through my eyes from my brain. What a joy to participate in the transmutation of dried beetles into immaculate carmine. I felt more like the sorcerer’s apprentice than merely Humphrey Murray’s junior technician.
A more down-to-earth business experience was the discovery that the firm profited by buying kilogram cartons of dye from ICI and packaging it in one-gram bottles. They then sold this back to their customers, which included other ICI departments, for as much as thekilogram cost. I stayed with the firm until July 1939. Humphrey Murray was by then, I think, fed up with my unbridled curiosity and chose to transfer me to work with one of their customers, the blueprint manufacturers, Norton and Gregory. I had an extraordinary sense of fulfilment as I worked out my apprenticeship as a scientist. I am full of gratitude to Humphrey Murray and to Tyrell, and my friends of that extraordinary firm.
In the spring of 1939, the students at Birkbeck and other evening-class colleges in London received a rude shock. The government announced its intention to conscript all fit young men for military service. Full-time students would be exempt but not part-time students like those at evening classes. My fellow students at Birkbeck shared my view that this was monstrously unfair. Here were we working both in the daytime and at night, the most diligent of students. How dare they penalize us? The political blood in my veins began to boil and I drew up a petition
Similar Books
