Calendar, Sumatran, cylindrical, bamboo, maker unknown, Sumatra, 20th century
This slide rule is from the collection of calculating instruments assembled by Assoc. Professor Allan Bromley. His collection provides examples of most forms of calculating devices made from the early 18th to the late 20th centuries. Slide rules constitute a substantial proportion of this collection.
Over the 19th and much of the 20th centuries the slide rule was the primary instrument for calculation used by many people engaged in the trades and in engineering. Although originally invented in the 17th century, and widely used for gauging (or estimating the quantities of certain products such as alcoholic spirits) it took until around 1850 for the slide rule to become generally popular. However for those engaged in estimating (ie, gauging) various quantities of goods in use in the liquor, building and agriculture trades, and for calculating the excise duty to be paid on these goods, numerous kinds of sliding rules with useful scales were developed.
Specialist slide rules of many kinds were developed over the period of their use. In the 20th century many special purpose slide rules were made from various kinds of paper or card, and from light sheet plastics once plastics became a common place in the later part of the century.
This may be a Batak calendar from traditional Sumatran culture. They are used to determine propitious days for ceremonies and not the date. They are written down by the student Batak medicine man (who is different from a shaman) as dictated by his teacher. The student must learn the 19 signs (plus the vowel signs) of the Batak alphabet from his Batak teacher.
[E. M. Loeb, review of Joh. Winkler: Die Toba-Batak auf Sumatra in gesunden and ranken Tagen (Stuttgart, 1925) in American Anthropologist, New Series, Vol. 32, No. 4 (Oct. - Dec., 1930), pp. 682-687
It is possible that this is actually a medicine container rather than a calendar although it does have the calendar tables incised around it.
Bromley note: "Incised on surface of a segment of Bamboo stem with a stopper in the form of a carved wooden head. The string by which the head was secured to the calendar was frayed through and removed. (remnants placed inside). The interior possibly originally held a paper roll or similar. This is now lost I do not know the nature or use of the calendar."
[Stopper presently missing]
Bromley purchased from Old Ark, City Road (Sydney) - 7/9/84 - $17.