Aftalion, A. (English spelling) AftalionA

Japanese: Aftalion，A.（英語表記）AftalionA

...The gestation period of investment refers to the time that elapses from the start of production of capital goods to their completion and start of operation. The term was first used by Cambridge University economists AC Pigou and D. Robertson, but the basic concept was developed by the Frenchman Albert Aftalion (1874-1956). In 1913, Aftalion used the famous analogy that since it takes time for the temperature in a room to rise after lighting a fireplace, if you keep burning coal because it's cold, the room will eventually become unbearably hot. He developed a theory of economic growth that states that after a period of economic upswing, when investment continues in line with the increase in demand for consumer goods, the boom will collapse and the economy will continue to decline as capital equipment that has undergone a gestation period begins production.

From [Acceleration Principle]

... By focusing on this relationship, it is possible to explain how a slowdown in product demand leads to a decrease in investment demand, resulting in economic stagnation. The first person to clearly discuss this was Albert Aftalion (1874-1934, a French economist born in Bulgaria).

*Some of the terminology that mentions "Aftalion, A." is listed below.

Source | Heibonsha World Encyclopedia 2nd Edition | Information

Japanese:

…投資の懐妊期間の意味で，資本財の生産着手からそれが完成して稼働しはじめるまでに経過する時間を指す。この語を初めて用いたのはケンブリッジ大学の経済学者A.C.ピグーとD.ロバートソンであったが，基本的概念の発案者はフランスのアフタリオンAlbert Aftalion(1874‐1956)である。アフタリオンは1913年，暖炉に点火してから部屋の温度が上がるまでには時間がかかるため，寒いからといって石炭をたきつづければ，やがて部屋は耐えられないほどに暑くなるという有名な比喩を用い，消費財需要の増加に合わせて投資が続く景気上昇期の後には，懐妊期間を経た資本設備が生産を開始するに至って，ブームの崩壊と景気後退が続くという景気理論を展開した。…