In July 1858, the Victorian Government Astronomer, Dr Robert L J Ellery, took charge of a major new survey project which involved the marking of meridians of longitude and parallels of latitude on the ground. These markings could then be progressively subdivided into blocks of one tenth of a degree (about ten kilometres), which at the time was considered a suitable size for further subdivision by contract survey.
This approach was well suited to the flat-to-undulating country west of where the Hume Highway now lies. East of the Hume, however, a process of triangulation from hill top to hill top became necessary because of the more mountainous nature of the terrain. Triangulation, or the measuring of the three angles of a triangle by theodolite, offered a far more rapid and economic method of providing accurate positioning. However a triangulation network begins with the primary triangle, the sides and angles of which must be determined with the greatest accuracy attainable, and the length of one side of one of the triangles must be accurately known. The area around Werribee was ideal for establishing such a baseline.
This first baseline is marked at each end by solid masonry stones. The South Base Stone is a large cylindrical block of basalt about 500mm in diameter set 5 feet (1500mm) into the ground with the top flush to ground level. A raised stone torus set in the centre with a gunmetal plug indicates the exact point from which the baseline was measured. The base stone is covered with a sculpted square cap stone with iron eyes to aid in lifting. The North Base, roughly 5 miles away to the north-west, is marked by similar stone and cap. Today, modern surveying equipment such as laser measuring instruments and GPS receivers can measure such distances easily. In 1858 however, Ellery faced an enormous problem in measuring the base line to the accuracy required. That he succeeded admirably may be seen in the fact that his results vary from modern measurements by less than one centimetre per kilometre over the total 17km length of the new base line.
At the posted coordinates, you are standing at a display commemorating Dr Ellery’s achievement, and describing the painstaking methods his team used. You will need to answer some questions from this display in order to find the cache.
1. How many panels make up the display? Panels = a
2. How many photos/illustrations (not maps) are included? Photos = b
3. What is the last year mentioned on the first panel? Year = cdef
4. How many people are shown in the second photo? People = g
5. How many tent bearers are mentioned? Bearers = h
The original location for the cache will be unavailable for about 18 months for works associated with the Hoppers Crossing Level Crossing Removal Project. We have moved it to a temporary location for the duration. You will now find the hidden micro at S37 53.gce, E144 42.(f-b)(e-h)d until the original location is available again. You may be being watched on weekdays, so a little stealth please.
The Heritage-Listed South Base Stone itself is not far away at S37° 53.108 E 144° 41.854, sitting unobtrusively inside a cyclone mesh fenced enclosure. To see it through the fence, follow the foot track beside the railway that starts at the end of the new car park on the south-west side of the railway level crossing. At the time of placement, the gate leading to this track was open, but may not always be so. Alternatively, you should also be able to see it from the small car park behind 299 Princes Highway, opposite the Hospital, but we recommend parking in the service road outside and walking in.
See these Wyndham History and Heritage Victoria sites for more details of Ellery's project.
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