中國的第二次銅器時代：為什麼中國早期的炮是用銅鑄的？

中國文明地區是世界上最早使用火藥和發展鑄鐵技術的地方。火藥由蒙古人傳到歐洲之後，發展為砲(bombardment)，由於缺乏鑄鐵技術，所以最初使用「熟鐵」(wrought iron)鍛造。但是這樣的砲管不堪使用，因此不得不回頭使用青銅，在十四世紀中晚葉開始了麥克尼爾(William H. McNeill)所謂歐洲兵器的第二次青銅器時代。不過，中國鑄鐵的技術也於約略同時傳進歐洲，大約一四五○年左右，歐洲已能用鐵來鑄造大砲。中國人雖然最早發明鑄鐵技術，但現存最早的砲都出現在蒙古人開始征服歐亞大平原的時代，而且在中國所發掘出來的砲都是銅鑄的。原因是，宋代以後中國北方大量用煤取代了木炭，而北方的煤含硫量甚高，熔煉(smelt)鐵礦砂時會使鐵的品質改變。用這種鐵鑄砲，堅硬度不可靠。因此他們放棄用鐵，而以銅來鑄砲。於是中國在南宋末也進入了第二次銅器時代。銅鑄的砲固然比較可靠，但是昂貴得多。宋元時代的人已注意到中國的鑄鐵品質不好，卻不瞭解箇中關鍵。這是中國第二次銅器時代無法結束的原因。英國於一七○四年發明提煉焦炭(coke)技術，把煤裹的雜質提煉乾淨，進而控制其成分，方便於熔煉鐵砂時減少雜質或適度加入其他元素以冶煉各樣的鋼鐵，銅砲從此完全消失。中國人早在明代(1599)已發展出焦炭技術，卻未詳細追蹤鑄鐵品質不佳的原因，因此無法大量鑄造鐵砲和改進品質。第二次銅器時代是人類歷史上一個重要的轉捩點，其意義要在歷經幾個世紀的探索之後才充分彰顯出來。

關鍵字

鑄鐵；第二次銅器時代；石炭；火藥；突火槍；炮／砲

並列摘要

In his brilliant study, The Pursuit of Power, William McNeil suggested that the development of cannons in the West went through a stage of ”Second Bronze Age”, approximately 1453~1543, because wrought iron, the mainstay of Western iron technology, was not fit for manufacturing cannons. Without cast iron technology, which was first applied to the casting of cannons around 1450, the West had to resort to using bronze. Interestingly, early specimens of Chinese cannons that date back to the turn of the 14(superscript th) century were also made of bronze. Iron cannons did not make their debut in China until slightly later, If the Chinese iron technology had been characterized by cast iron technology, then it would be quite strange that they did not apply it to the fashioning of cannons, which were to appear towards the end of the Southern Song (1127~1278) after the first formula of gunpowder was recorded in around 1040. The manipulation of gunpowder explosion necessitated the use of hard metal and especially delivery barrels. Cast iron would ideally serve this purpose, However, it seems that the Song iron technology could not meet the needs too. This is most likely a consequence of the use of coal (shitan), instead of charcoal, to smelt iron ore that became popular in the Northern Song times (960~1126). The coal from Northern China contained high percentages of sulfur. Cast iron that contains more than 0.5% of sulfur will lose its hardness. Without the skill to extract sulfur and other impurities from coal, the Chinese artisans were not able to cast cannon barrels hard-enough to withstand the explosive power of gunpowder in use. From the Song through the Ming (1368~1661), the Chinese increasingly used the so-called ”shutie”, a kind of iron similar to Western wrought iron. Like wrought iron, however, shutie is not fit for manufacturing cannons, The invention of coke in 1704 was the decisive moment when, one can say, the European ”Second Bronze Age” in cannon-making came to its full cycle. The Chinese, indeed, had by 1599 developed the skill to make coke, but for various reasons they never seemed to have been able to produce good-quality cast iron cannons. The second Chinese Bronze Age thus ended in a way fundamentally different from that of Europe. It never actually ended until the Europeans introduced their iron cannons technique to China. These comparative experiences of cannon-making and cast-iron technology show that civilizations do not have to take the same route of development. Chinese artisans had been more fascinated with how to improve iron implements for daily use, and were satisfied without having to better the quality of cast iron essential for making cannons. On the other hand, Europeans seemed to have more systematically wanted to manufacture weapons that represented power, notwithstanding economic irrationality. This last point echoes McNeill's putative remark on Europeans' ”unintelligible behavior”. However, it was the Chinese ”rationality” that led to its failure to comprehend the military implications of technological development.