For some reason, the full map of the Forbidden City published by the National Palace Museum in Beiping in 1948 marked Chong Lou（崇楼） as Sui Lou（祟楼）。It seems that it is not a typo, because the English label matches it. The exact reason remains to be determined.
永和宫后院的井亭非常别致，内置一架故宫内也不多见的铸铁压水机，上面铸有THE GOULDS M’F’G. CO. 的字样(The Goulds Manufacturing Company的缩写）。该公司原为纽约的一家水泵公司，始建于1848年。并于1869年起改名为The Goulds Manufacturing Company。该名称如今已经成为赛莱姆国际公司（Xylem Inc.）旗下的品牌。永和宫最后一次重修是在光绪十六年（1890年），这架压水机很有可能是在此次修缮中安装的（有待确认）。仔细观看，水泵底座已经破碎，如果以1890年计，到今年（2019年）也才129岁。
The well pavilion in the backyard of Yonghe Palace is very unique. There is a cast-iron hand press pump in it. You can find the name of THE GOULDS M’F’G. CO. casted on the pump. The manufacturer was originally a pump company in New York, started to use the name since 1869. It is now a brand owned by Xylem Inc. The palace was last restored in the 16th year of Guangxu (1890) , and it is likely that the press pump was installed during the renovation (to be confirmed) . Look carefully, you’ll find that the pump base has been broken. If you start counting in 1890, it will be 129 years old this year (2019).
In the north sides of Jiyi Hall （集义殿）and Benren Hall（本仁殿）, there are two stone bases of bronze vats separately. At first I mistook them for dry wells because of the rare grey-brick plinth, thanks to the advice of a Weibo friend. When the bronze vats were removed, I am reminded of the Japanese dedication of copper and iron campaign in 1944. In response to the incident, the The Palace Museum conducted an inventory of 277 bronze vats in the Forbidden City. It includes: type 1: 98 pieces of bronze vats with Ming and Qing Dynasty manufacture signature mark; type 2: 125 pieces of bronze color similar to those made in the Ming Dynasty but without manufacture signature mark; type 3: 54 pieces of no identification and the style can not be judged to belong to the Ming Dynasty. Finally, on June 19, 1944, the Palace Museum handed over 54 bronze vats belonging to the third category of no identification to the Japanese army . As to whether these lost copper vats were included in the list of 54 unidentifiable copper vats, a check of the inventory at that time will make it clear. Another question remains to be answered. It is now generally accepted that there are 308 bronze vats in the Forbidden City, 31 of which are different from the 277 counted in 1944.
A Weibo friend mentioned that in 1944, the Hall of Literary Brilliance was still under the jurisdiction of the National Museum of Art, Peiping.
The ancestral pole is located at the southeast side of the Kunning Palace, which is the northeast corner of the Hall of Union. The catalog number is No. 00204055, and is recorded as a Manchurian pole for offering sacrifices to the gods. Now only the pedestal of the sacred pole exists.
The sacred pole is called “Soluo” in Manchu, and there is also the saying of Soluo’s sacred pole. The shape of the pole is shown in figure 6. The debate continues as to whether the sacred pole should be used for ancestor worship or for offering sacrifices to the gods .
The sacred pole outside the palace, also known as the Ancestral Pole. According to the Manchu custom, when offering sacrifices to heaven, the altar table is placed in the northeast of the sacred pole. On the altar were neck bones, gall bladders, shredded meat and rice. When the sacrifice is over, place the neck bone at the top of the pole, the gallbladder, shredded pork and rice into a bowl, and then the emperor and Queen prayed for blessings. 
In Qing Dynasty, the Kun Ning Palace was rebuilt and renovated three times according to the Manchu style in Shunzhi 12th year (1655) , Kangxi 19th year (1680) and Jiaqing 3rd year (1798) . As for when the sacred pole began to erect in the Palace, there is no record found. However, the ancestral poles can be seen from the photos of 1900-1925 (Fig. 6-Fig. 9). The pole is missing from the 1982 photo. The specific age of erecting and removing the ancestral sacred pole remains to be verified.
According to the Sikuquanshu, the sacred pole was taken from the pine trees of Yanqing District. Click to view details.
故宫丛刊之三 故宫摄影集 第一编第二册 交泰殿坤宁宫 清室善后委员会 30页
The stone flagpole pedestal is located in the front southwest corner of the Hall of Imperial Peace (钦安殿：Qin An Dian) , and built on a marble base (figure 1). The four sides of the pedestal are engraved with double dragons frolicking with magic pearl (figure 2). The catalog number 204008 of the Palace Museum collection is clearly visible (figure 3). Checked it out online, it’s called a copper-plated flagpole pavilion, and it looks like the data entry is wrong. Later, I saw Guan Jing’s paper “sincerely pray for the Hall of Imperial Peace Dojo” , it turns out that the description here is not about the flagpole itself, but the top structure of the pole, the baoding (literally, “treasure top”) . According to Guan Jing, the flagpole was recorded as: “Five Dragons Holding the Flagpole“. The pole is nine zhang, five chi long (about 31 meters). On the top of the pole is a “gold-plated copper square pavilion with double eaves” baoding. There is a silver box in the baoding, which contains “the Celestial Venerable father of the Primordial Beginning tells the wonderful Sutra of northern Zhenwu” (元始天尊说北方真武妙经) and “Primal Beginning Boundless Salvation Highest Level Mystical Scripture“ (元始无量度人上品妙经).
The four corners of the marble base have turtle (southeast) , fish (southwest) , crab (northwest) and shrimp (northeast) patterns (figure 4). In the Hall of Imperial Peace, there is a bronze statue of Zhenwudadi (真武大帝), also known as Xuanwu, the God of water . Therefore, the base engraved with these “shrimp soldiers and crab generals” is a matter of course.
“Originally, the stone pedestal held a wooden pole that rose above the Forbidden City. If you look southeast from the White Pagoda（白塔） of Beihai Park（北海公园）, only this pole was picked out from the yellow tiles and green shades, and becoming a visible symbol of the Imperial Garden（御花园）.”
From the photo of Lin Jing, you can clearly see the flagpole (figures 5, 6). The photos were taken in 1901 and 1920s . High flagpole can also be seen in the photos taken by Gamble from Coal Hill (景山) in 1918 click to view and from the Palace of Gathered Elegance (储秀宫) in 1924-1927 click to view  . And Morrison’s 1933-1946 photo did not see the flagpole , click to view. Therefore, we can conclude that the flagpole disappeared between 1933 and 1946. It is not known why the flagpole was removed or where it is kept today. No relevant information was found.
In Guan Jing’s paper, also provides an old photo, captioned as “the scene of the construction site of the Five Dragons Holding the Flagpole”, and noted at the end of the Qing Dynasty. However, it is clear from the photo that the base of the flagpole has already decayed. Based on the above conclusions, this photo should show the removal of the flagpole between 1933 and 1946.
下面这张照片翻拍自单霁翔的影集《故宫藏影——西洋镜里的皇家建筑》，为甘博（Sidney D. Gamble ）在1924-1927年间所摄：553A_3205）。从中可以看到幡杆的更多细节。
This photo below is from Shan Jixiang’s photo album Hidden Shadows in the Forbidden City: Imperial Architecture in the Shot of Foreigners. . The original photograph was taken by Sidney D. Gamble between 1924-1927, photo ID:553A_3205. Details of the flagpole can be seen in this photo.
[306-1751 and 553-3205], Sidney D. Gamble Photographs, David M. Rubenstein Rare Book & Manuscript Library, Duke University.
 [W86461-1] , Hedda Morrison Photographs, Harvard University, Harvard College Library Harvard-Yenching Library