The reason was that although Xin Yi Xiang Fa Yao contained over 60 complete views, part views and detail drawings of the clock tower, the only part covered more or less completely is the celestial globe--there are many gaps in the dimensions of the other parts.
原來雖然《新儀象法要》附有全圖、分圖、詳圖六十多幅，但記載最明確的是渾象，其他有關呎寸的部份卻是缺漏甚多。