【推荐1】The Quwwat-ul-Islam Mosque complex in New Delhi is home to an ancient wonder of metal work — the Iron Pillar (柱) of Qutub Minar, which is very unusually resistant to rust (铁锈). This 1,600-year-old monument measures 7.21 meters tall, has a diameter of 41 centimeters and weighs about 6 tons.

Even though it has spent all that time outdoors, the Pillar of Qutub Minar shows almost no sign of rust damage. There was a time when many believed that the rust-resistant pillar was made out of some mysterious, non-earthly metal, while others believed that whoever made it used an extremely modern technique that was lost in the mists of time. That second theory is technically true, as metallurgists showed in a paper published in the journal Current Science.

R. Balasubramanian, co-author of the study, called the pillar “living evidence for the skill of metallurgists of ancient India”, explaining that the iron structure features a protective layer called “misawite” — a substance that forms a barrier between metal and rust. The formation of misawite is caused by the high phosphorus (磷) content in the iron.

While modern iron has a phosphorus content of under 0.05%, the iron that the Iron Pillar of Qutub Minar is made of contains as much as 1 percent phosphorus. According to Dr. Balasubramanian, instead of removing the phosphorus from the iron as workers do today to prevent the metal from breaking up, ancient people kept it in, and simply kept hitting the pillar hard with hammers to push the phosphorus from the core towards the surface. This kept the iron strong, and also led to the formation of the misawite barrier.

As is often the case with these ancient wonders, they can be easily harmed by humans. The pillar gained a reputation for bringing good luck to whoever managed to wrap their arms around the metal structure, and more and more people engaged in the practice over the years. But the misawite barrier is an extremely thin layer, so the practice has led to a visible discoloration of the pillar near its base. Luckily, authorities realized the danger and built a protective fence around the pillar.

【推荐2】A new study analyzing stone tools from southern China provides the earliest evidence of rice harvesting, dating to as early as 10，000 years ago. The researchers identified two methods of harvesting rice, which helped start rice domestication(家庭种植).

To harvest rice, some sort of tools would have been needed. “For quite a long time, one of the puzzles has been that harvesting tools have not been found in southern China from the early Neolithic period or New Stone Age (10，000－7，000 Before Present)—the time period when we know rice began to be domesticated” says lead author Jiajing Wang, an assistant professor of anthropology at Dartmouth.

“However, when archaeologists (考古学家) were working at several early Neolithic sites in the Lower Yangtze River Valley, they found a lot of small pieces of stone, which had sharp edges that could have been used for harvesting plants.”

“Maybe some of those small stone pieces were rice harvesting tools, which is what our results show.”

In the Lower Yangtze River Valley, the two earliest Neolithic culture groups were the Shangshan and Kuahuqiao.

The researchers examined 52 flaked (成薄片的) stone tools from the Shangshan and Hehuashan sites, the latter of which was occupied by Shangshan and Kuahuqiao cultures.

To determine if the stone flakes were used for harvesting rice, the team conducted use­wear and phytolith residue (植物石残渣) analyses.

For the use­wear analysis, micro­scratches (划痕) on the tools’ surfaces were examined under a microscope. The results showed that 30 flakes have use­wear patterns similar to those produced by harvesting siliceous (silica­rich) plants, likely including rice.

Through the phytolith residue analysis, the researchers analyzed the microscopic residue left on the stone flakes known as “phytoliths” (silica skeletons of plants). They found that 28 of the tools contained rice phytoliths.

“What’s interesting about rice phytoliths is that rice husk and leaves produce different kinds of phytolith, which enabled us to determine how the rice was harvested,” says Wang.

The findings from the use­wear and phytolith analyses illustrated that two types of rice harvesting methods were used—“finger­knife” and “sickle” techniques. Both methods are still used in southern China today.

【推荐3】“A lot of early archaeology(考古学)was about finding things that are beautiful and museum-worthy,” says archaeologist Sarah Graff. Bits of broken artifacts or boring-looking items from the field of food preparation were sometimes thrown aside with the dirt that wasn’t being analyzed, she says, and scholars used to be more excited by the lives of kings. “They didn’t really think that things that had to do with domestic labor would have anything to do with politics or economics.”

But researchers are now finding more of those connections and trying to mine ancient pots to learn about the foods once prepared in them.

Biogeochemist Richard Evershed made his first identification of fat from foods in the walls of medieval(中世纪的)pots dating from 950 to 1450 at a site in England. With signs of fat, probably from making cheese, those pots are thought to have been used for baking bread. The scientists also discovered the leaf wax(蜡)of cabbage, which was likely cooked with meat. Consuming meat, cheese, butter and bread, the medieval peasants weren’t doing too badly, says archaeologist Julie Dunne, Evershed’s teammate.

Since 2014, some researchers have dived into experimental archaeology by cooking various recipes in store-bought pots. They used the same pot to cook the same recipe 50 times, and finally switched to a new recipe, cooking four meals. After a year, the pots’ outer layers held signs of all the recipes but contained more remaining parts of the last meals. But the fatty substances within the inner layers of the pots built up over many times of cooking, which left obvious proof of the former recipes. The latest cooking events, however, was not the case, as archeologist Melanie Miller and her teammates reported in 2020 in Scientific Reports.

Miller and her team will continue cooking their tasteless meals. Cooking is “one of the most common things that humans have across time and space,” she says. Food and food practices signify traditions, politics, status, identities, upbringings and more. Food preparation reveals much. “It’s a daily practice…usually representative of all these much larger questions about our place in the world.”

【推荐2】Nearly two decades ago when the Google Books Project digitized and freely distributed more than 25 million works, book publishers argued that free digital distribution weakens the market for physical books. However, new research from Imke Reimers and Abhishek Nagaraj reveals that the opposite—increased demand for physical books, through online discovery—could be true.

The two researchers focused on a particular part of Google Books’ digitized works: those from Harvard University’s Widener Library, which helped seed the project in its early days. The condition that enabled their experiment: Harvard’s digitization effort only included out-of-copyright works, published before 1923, which were made available to consumers in their entirety. The works from 1923 and later were still copyrighted and not digitized.

The researchers analyzed a total of 37,743 books scanned (扫描) between 2005 and 2009. They looked at sales for the two years before this digitization period and the two years after, and found clear differences in the increased sales between digitized and non-digitized books. Approximately 40% of digitized titles saw a sales increase from 2003-2004 to 2010-2011, compared to less than 20% of titles that were not digitized. The increase in sales was also found to be stronger for less popular books.

“If a book is readily available online, people may decide that it’s a useful book and want to buy it,” Reimers said. “The ‘discovery effect’, which even increased the sales of a digitized author’s non-digitized works, is a strong driver of increased sales. It’s not a huge jump in sales, but it’s still good news for publishers.”

“And book lovers,” Reimers said, “are known for their preference for physical books, as opposed to digital versions, which could also play a role.” She added, “Whenever I talk to people about my research on books, at some point they all say, ‘I just love the feel of a book in my hand.’”