Abstract. The astronomer Manuel Johnson, a future President of the Royal Astronomical Society, recorded the ocean tides with his own instrument at St. Helena in 1826–1827, while waiting for an observatory to be built. It is an important record in the history of tidal science, as the only previous measurements at St. Helena had been those made by Nevil Maskelyne in 1761, and there were to be no other systematic measurements until the late 20th century. Johnson's tide gauge, of a curious but unique design, recorded efficiently the height of every tidal high and low water for at least 13 months, in spite of requiring frequent re-setting. These heights compare very reasonably with a modern tidal synthesis based on present-day tide gauge measurements from the same site. Johnson's method of timing is unknown, but his calculations of lunar phases suggest that his tidal measurements were recorded in Local Apparent Time. Unfortunately, the recorded times are found to be seriously and variably lagged by many minutes. Johnson's data have never been fully published, but his manuscripts have been safely archived and are available for inspection at Cambridge University. His data have been converted to computer files as part of this study for the benefit of future researchers.

中文翻译：

---

曼努埃尔·约翰逊（Manuel Johnson）在圣赫勒拿岛（St.Helena）的潮汐记录

摘要。未来的皇家天文学会主席天文学家曼努埃尔·约翰逊（Manuel Johnson）在等待建造天文台的同时，用自己的仪器记录了1826–1827年在圣赫勒拿岛的海洋潮汐。这是潮汐科学史上的重要记录，因为圣海伦娜以前唯一的测量是Nevil Maskelyne于1761年进行的，直到20世纪后期才进行其他系统测量。约翰逊的潮汐计好奇而独特的设计有效记录了每个潮汐高低水位的高度至少13个月，尽管需要经常重新设置。这些高度与基于当前同一地点潮汐仪测量值的现代潮汐综合非常合理地比较。约翰逊的计时方法未知，但是他对月相的计算表明，他的潮汐测量值被记录在当地表观时间中。不幸的是，发现记录的时间严重且可变地滞后了许多分钟。约翰逊的数据从未完全发表过，但他的手稿已被安全地存档，可以在剑桥大学查阅。为了将来的研究人员的利益，他的数据已转换为计算机文件，作为本研究的一部分。