Sir Isaac Newton and Alchemy
Sir Isaac Newton is most famous for the quantification of gravitational attraction, discovering that white light is actually a mixture of immutable spectral colours, and the formulation of calculus. However it is less well documented that Newton spent 30 years engaged in the study of the mysterious art of alchemy, or as it was more commonly known then, chymistry.
Only a tiny fraction of Newton’s work on alchemy has been published but he wrote around a million words on the subject, including laboratory notes, indexes of alchemical substances and transcripts from other sources. On his death in 1727, Newton had over 100 manuscripts filled with alchemical material, sold by auctioneers Sotheby as part of a larger collection in 1936. This side of Newton was often an embarrassment to his admirers. His first biographer, John Conduitt, like many commentators who followed, played down the role of alchemy (and other pursuits) in Newton’s work, stating;
“When he was tired with his severer studies his only relief and amusement was going to some other as History and Chronology or Divinity and Chymistry”.
Just how important the study of alchemy was to Newton only began to be recognised in 1947, when John Maynard Keynes, who bought much of the work from Sotheby, declared in his essay, ‘Newton, the Man’; “Newton was not the first of the age of reason. He was the last of the magicians”.
Questions 1 – 4
Choose the correct letter, A, B, or C.
1)Newton realised that white light was made up of different what?
2) What was alchemy originally called?
C. an art
3)Many thought Newton was what?
B. an embarrassment
4) What did Keynes call Newton?
C. a magician
Now look at the reading passage about ants and aphids and answer the questions that follow.
Ants secrete aphid tranquilizer from their feet
Ants and aphids are known to have a complex relationship. The aphids provide the ants with a food source – the sugar-rich honeydew they excrete when eating plants – and, in return, the ants protect the aphids from ladybirds and other insects that prey on them.
To ensure a constant supply of honeydew, some ant species cultivate large numbers of aphids, and prevent them from straying too far from the colony by biting and damaging, or even completely removing, their wings. The ants also secrete a chemical from their mandibles which inhibits wing development in juvenile aphids.
Ants communicate with each other using a large repertoire of chemical signals, which are actively secreted onto surfaces from exocrine glands on the legs. These signals can recruit nest-mates to food sources, and are also used to mark a colony’s territory. Ants secrete chemicals passively too. As an ant moves, hydrocarbons are shed from the cuticle (the waterproof outer lining of the exoskeleton), leaving a chemical trail.
Ants use behavioural signals called semiochemicals to manipulate aphids’ nervous systems. (Ant’s own behaviour can be manipulated too, by parasitic fungi.) Earlier work had shown that the presence of ants can somehow tranquilize aphids and limit their motor functions, but whether or not this required direct contact between the ants and aphids was unclear.
Using digital video cameras to measure their walking speeds, Tom Oliver of Imperial College London, and colleagues from Royal Holloway and the University of Reading have now shown that aphids move much more slowly on paper that had previously been walked on by ants than on plain paper. They believe that the chemicals laid down in the ants’ footprints are used to maintain an aphid “farm” near the ant colony.
Maintaining a populous aphid farm in a small area is obviously beneficial to the ants, as it would provide them with large quantities of honeydew. However, the relationship between the two species is complex, and it seems that the ants’ manipulation of the aphids’ behaviour is exploitative.
Normally, aphids wander off to new locations when conditions become crowded, to establish new populations nearby. And although ant-attended aphid populations are bigger and live longer than those not attended by ants, the ants prevent the aphid dispersal that is necessary to maintain a stable meta-population, and makes the aphids more vulnerable to parasites.
Questions 1 – 5
Choose the correct letter, A, B, C or D.
1) How do ants ensure they have regular supplies of honeydew?
A. they damage their wings
B. aphids are made to secrete a chemical
C. they find more juvenile aphids
D. they bite their legs
2) How do ants affect aphids’ nervous systems?
A. by using parasitic fungi
B. by touching their legs
C. by making a noise
D. by using chemicals
3) When do aphids walk more slowly?
A. when they walk on paper
B. when they are with other aphids
C. when they are on video
D. when they walk on chemicals secreted by ants
4) How can we best describe the relationship between the ants and aphids?
B. win – win
5) What do aphids do if the area becomes overpopulated?
A. start a new colony
B. start a stable meta-population
C. they grow bigger
D. they live longer than ants
Get your Reading eBook to learn and practice different types of questions