"You will as early as possible return by the road across Liverpool Plains so as to fall into the return route of the late expedition before you leave the settled districts, and in this manner you will recross the Balonne at St. George's Bridge, take the route back to Camp (83), and thence by the route along the Maranoa to Camp (XXIX), beyond which you will proceed as hereinafter detailed, with reference to the accompanying tracing of my survey.
"You will cross the Maranoa at Camp (XXIX), and continue along my return route until you reach Camp (75). I beg you will be particular so far in looking for the track of my party returning, as you will perceive by the map that many very circuitous detours may be thus avoided. But beyond Camp (75), about seven miles, you will have to leave my return track on your right, and not cross a little river there at all, but go along my old advance track to Camp (XXXIV). Thence you will proceed by Camps (XXXV) and (XXXVI), in order to approach the bed of the Warregò in the direction of my ride of 14th June, in a general N. W. direction. It is very desirable that you should keep my horse tracks there; but this I can scarcely expect, and I can only therefore request that you will proceed as closely in that direction as you can. The bed of the Warregò may be looked for at a distance further on, equal to that of my ride of 14th June.
"You will next pursue the course of the Warregò upwards towards Mount Playfair, which the accompanying map will be sufficient to guide you to. You will follow up the Cùnno Creek, leaving Mount Playfair on your right or to the eastward, and you will thus fall into the line of my horse-track about the spot where I spoke to an old native female. I wish you would then take some pains to travel in the direction of my track from the head of Cùnno through the Brigalow, which is comparatively open, in the direction of my bivouac of 11th September.
"Keeping the direction of my track of next day, you will arrive at a low, but stony, ridge (A) (across which you must be careful how you pass your carts, but it is of no breadth), and you will descend into a flat, from which you will ascend another stony ridge (B), of no greater height but more asperity than the first, and covered with fallen timber. You will have about a mile of that sort of difficulty to deal with on the higher part, but by turning then to the right, you will fall into a well watered valley, which will lead you to the Nive. In the whole of your route thus far, you can meet with no difficulty in tracing it, guided by the map, and following these instructions; but if Douglas should be with you, he will no doubt recognize the country through which he passed with me. It is very important that you should keep that route, as leading to the Victoria in a very straight direction from Sydney, and a direction in which, should your return be delayed beyond the time for which your party is to be provisioned, it is probable, that any party sent after you to your aid or assistance would proceed to look for you. After you shall have reached the Nive and Camp (77), you cannot have any difficulty in finding Camp (72) near the Gap, and from that valley you have only to follow down the watercourse to be certain that you are on my track to the Victoria, and, as you have been instructed to take an expert native with you, you ought to find still my horse's track across the downs, cutting off large bends of the river. But beyond Camps 16th September or 1st October, you must keep by the river along my route back, and not follow the circuitous track which I took through Brigalow to the westward. After about four miles by the river, you will see, by the map, that my return track again crossed the outward track over the downs, so that you may fall into the route westward of the great northern bend of the Victoria. I fear you must depend on the latitude, pace measurement, and bearings, for ascertaining the situations of my camps of 29th September and 28th September. You will see by the map how generally straight my journeys were between these points, and how important it would be for you to know the situation of the camp of 28th September, that you may thence set out westward in the direction of my return route, instead of following the main channel throughout the very circuitous turn it then takes to the northward. Beyond the lowest point attained by me, or the point (wherever that may be) to which you will be able to identify the accompanying map with my track, of course it will be your duty to pursue the river, and determine the course thereof as accurately as your light equipment and consequent rapid progress, may permit. You may, however, employ the same means by which I have mapped that river so far; and, for your guidance, I shall add the particulars of my method of measuring the relative distances. If you count the strokes of either of your horse's fore feet, either walking or trotting, you will find them to be upon an average, about 950 to a mile. In a field-book, as you note each change of bearing, you have only to note down also the number of paces (which soon becomes a habit); and to keep count of these, it is only necessary to carry about thirty-five or forty small pieces of wood, like dice (beans or peas would do), in one waistcoat pocket, and, at the end of every 100 paces, remove one to the empty pocket on the opposite side. At each change of bearing, you count these, adding the odd numbers to the number of hundreds, ascertained by the dice, to be counted and returned at each change of bearing to the other pocket. You should have a higher pocket for your watch, and keep the two lower waisctoat pockets for this important purpose.
"Now, to plot such a survey, you have only to take the half-inch scale of equal parts (on the 6-inch scale in every case of instruments), and allowing TEN for a hundred, the half-inch will represent 1000 paces. You may thus lay down any broken number of paces to a true scale, and so obtain a tolerably accurate map of each day's journey. The latitude will, after all, determine finally the scale of paces; and you can, at leisure, adjust each day's journey by its general bearing between different latitudes; and, subsequently, introduce the details. You will soon find the results sufficiently accurate to afford some criterion of even the variation of the needle, when the course happens to be nearly east or west, and when, of course, it behoves you to be very well acquainted with the rate of your horse's paces, as determined by differences of latitude. You will be careful to intersect the prominent points of any range that may appear on the horizon; and the nature of the rock also should be ascertained in the country examined: small specimens, with letters of reference, will be sufficient for this. Specimens of the grasses, and of the flower or seed of new trees, should be also preserved, with dates, in a small herbarium. But the principal object of the journey being the determination of the course of the Victoria, and the discovery of a convenient route to the head of the Gulph of Carpentaria, the accomplishment of these great objects must be steadily kept in view, without regard to minor considerations. Should the channel finally spread into an extensive bed, whether dry or swampy, you will adhere, as a general rule, to the eastern side or shore, as, in the event of any scarcity of water, the high land known to be there will thus be more speedily accessible to you; and I am also strongly of opinion, that you would cross in such a route more tributaries from the east than from the west. On arriving at or near the Gulph of Carpentaria, I have particularly to caution you against remaining longer than may be unavoidable there, or, indeed, in any one place, in any part of your route, where natives may be numerous.
"Having completed (at least roughly) the map of your general route, it will be in your power in returning, to take out detours, and cut off angles, by previously ascertaining the proper bearings for doing so; and when so returning, it would be convenient to number your camps, that the route and the country may be better described by you, and recognised afterwards by others. These numbers may be cut in common figures on trees; and if, as I hope, you should reach the Gulph, you can commence them there: you may prefix C to each number commencing with 1, thus avoiding any confusion with the numbers of my numbered camps on the Victoria.
"On returning to the colony, you will report to me, or to the officer in charge of the Survey Department, the progress and results of your journey.
"I have the honour to be,
Sir,
Your obedient servant,
"T. L. MITCHELL,
SURVEYOR-GENERAL.
"E. B. C. Kennedy, Esq. J. P.
Assistant Surveyor,
Sydney."