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procedure and argument are outside the possible scope of this report. I recommend that a member of the staff with mathematical knowledge be sent to Ceylon for three weeks to study the procedure of their excellent new levelling. If this investigation could be combined with the duty of representing Hong Kong at the 1931 Surveyors Meeting it would be advantageous, for at that meeting we shall visit the Liverpool Tidal Institute, and shall discuss other aspects of levelling.
9. Minor Methods of Surveying.—It is of small consequence to provide a reliable framework if the detail surveyor introduces plottable errors in his final offsets. My impression is that the minor surveyors are practical and reliable men, but their methods and their field books show that same untidyness which are elsewhere so apparent in this Department. As before, this fact is due to the lack of clear and practical depart- mental regulation. For example, each traverse tape is standardized at a particular tension and temperature. I saw a traverse, in the surveying, in which no spring balance was being used. Two values for the same length so measured differed apparently by only one part in thirty thousand, but there is no guarantee that both were not equally affected by systematic errors of the order of one in a thousand. The particular instance was one of no great importance, except in so far as it shows up the lack of clearly laid down routine. In actual offsetting I was told by one surveyor that offsets might be judged at right angles up to 30 feet and up to 15 feet by another, ie., the length measured but the angle judged. Both are far too long for work at 1/600, but it is not so much the actual field work as the lack of common rule which I desire to emphasize. Field books are incomprehensibe to the visitor. It is a matter of practice here that each Surveyor plots from his own measurement. This is dictated by expediency and lack of staff, and is not sound, but it explains the field books. The regulations of the future should lay down the type to be followed, and it should be such as to make plotting by an independent man an easy matter. Regulations should also include instructions for check lines and for inspection of the completed map (with graphic checks) by the European Surveyor-in-Charge.
As regards area computations, the present practice of mathematical calculation is sound for all Crown leases in urban districts. In the agricultural areas either the planimeter or the computing scale could be used. In either case, however, a final check should be made against the known areas of the full number of squares (of the grid) in which the cadastral plan lies. There is no other check upon paper distortion.
10. Instruments. The Department is moderately well equipped. The bands graduated for final measurement (100 feet to attach to 300 feet 1/16-inch bands) should be smaller in section.
CL
One good Theodolite (I recommend the new 34-inch Cooke Troughton and Simm's Tavistock") should be procured for additions to the control. Wooden legs (and not collapsible) should be specified.
"J
Two Brunsviga (novo) calculating machines and the appropriate tables of natural trigonometrical functions have already been mentioned, and certain stores for drawing and printing are enumerated in succeeding paragraphs.
11. Drawing The Surveyors draw and letter well, and are superior in standard to the minor draughtsmen employed in the Crown Lands Department. When a printing department has been begun particular care in securing firm, dense, black line will be necessary. I think too much lettering is being done, however. It is the normal practice to stamp names on cadastral maps and tracings, and boys can be employed for the purpose. Three palettes and a small supply of type should be got (through the Geographical Section, General Staff). The choice of type should be discussed with the home authorities. The style adopted for the 25-inch and 6-inch plans of the Ordnance Survey will be satisfactory.
At the present time much delay and waste of money occurs in the large amount of reducing (and occasional enlarging) by pantograph. Machinery is expensive at the moment, but soon saves itself in labour, and in all well-organized Survey Departments reduction is done by the camera. This point is of particular importance in compiling the 200 feet to the inch (1/2,400) plans from the 50 feet (1/600). An enlarging and reducing camera is, however, of less importance than the printing equipment recom- mended in the next paragraph, and might wait over for better financial times. Of equal importance is a press in which plans can be hung. Tropical conditions are against storage in drawers. Hung plans keep well, do not crease and break, and escape the cockroach.
Good tracing paper should be used in preference to tracing cloth.
12. Printing. Lithographic map printing is altogether distinct from letterpress printing, and is everywhere carried out by Survey Departments. There are few
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colonies now in which it has not started, and those (generally speaking) are able to rely upon the help of close neighbours. At the present moment there is no facility for printing official maps or plans in the whole of the Far East. That point should be borne in mind, because it might become important on political or defence grounds. (There is a very small machine, demi-size, in the Observatory, with no means other than litho. tracing of getting the work on to stone or zine). Sun-printing can be regarded as satisfactory or economical only for some half-dozen copies. The cadastral sheets (1/600, 1/2,000, &c.), should all be printed in small editions (say, 30 copies). The value of these expensive surveys is doubled by free cirenlation among technical departments, and the original, once recorded on zinc, keeps its shape, whereas paper records do not.
The policy should aim at the printing of maps and plans which affect the Colony. It is not a sound measure to order large stocks of maps to be printed in England. Maps and plans are soon out of date and editions should be just large enough to deal with current needs. The initial expense need not be large, and native staff can be trained to all the proper processes providing one good technical European printer be employed.
I recommend beginning with —
1 power proving press (double demy or larger).
1 Vandyke outfit.
Notes:-
(a) Both might he got in consultation with the War Office and both might be
second-hand;
(b) The existing are lighting system can be used;
(c) Electric drive should be employed;
(A whirler is hardly necessary (at first);
As
(e) Printing frames and all accessories included in the Vandyke outfit.
staff, one youngish all-round printer should be engaged (at the £400 start- ing rate), given 6 months' apprenticeship at the War Office or Ordnance Survey, and one month in Ceylon in which to study the effect of a hot and damp climate on the chemistry of zine printing and vandyking. This European could then start with three native printing apprentices and two native litho, drawing apprentices to build up his department. In a year's time he should be ready to install one litho. flat-bed machine (second- hand electrically driven and the same size as the proving press).
13. Regulations. Preceding paragraphs have emphasized the vital importance of clearing and crystalizing methods and processes, and describing them in printed regulations.
The departmental regulations of the Federated Malay States and Gold Coast surveys should be used as models. Writing these regulations in the light of local organization and survey characteristic will take time and thought. It may not be necessary to follow every process to its ultimate detail in the general regulations so long as minor separate printed instructions cover the whole ground.
14. Indering and Filing Air Photographs. There exist already a number of air- photographs covering the area of Hong Kong and the New Territories. In the future anny more will be taken. Unless proper indexes and storage boxes are made, it will be difficult to deal with them. Boxes should be made about 2 ft. by 10 in, by 8 in., in which sliding shelves. arranged as for a card index, carry the photographs. Each photograph should be indexed by the co-ordinate of its centre point, and each box should represent an area (say, the area of one of the 1/20,000 sheets).
15. Organization. At the present time the Survey Department is a part of the Public Works Department a body whose duties in Hong Kong are important and wide reaching. The present Director of Public Works has done much for survey, and has been able, to sonic extent, to give the survey branch its own staff and quarters. Survey is not, however, native to the engineering profession except in so far as every engineer is trained in surveying for his own ends. These ends do not, as a rule, include precise triangulation, traversing or levelling, and never include the revenue, topographical, cartographical and printing aspects of a survey office. I have now inspected 13 Colonial surveys. In one or two a start was made under Public Works; in no case of these thirteen does that still apply.
No doubt the public purse is the guiding factor, and the survey branch is probably not the only one included solely for the purpose of preventing clerical growth and perhaps checking the natural impulse to develop where developinent must needs wait upon revenue. I am unable to see at present in what way overhead charges are saved as regards survey. If the staff is to be regarded as interchangeable then efficiency
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