The minimum of cost is reached when the seams are of good thickness and comparatively free from slate, and can be entered on the end by a level entry above water and be mined upward; to which may be added natural pitch enough in the seams for the coal to be self-loading; that is, to run by gravity from the upper gangways to the cars on the main entry. And to these conditions may be added a number of different parallel seams close together with their bluff ends all coming up to a line in the most convenient way for entry and delivery. It is rarely the case that such an assemblage of favorable conditions can be found, and where they exist the successful future of the property is absolutely assured. [Sidenote: Cost at Gilman Mines.] In my opinion, the Gilman coal seams combine all the advantages above mentioned, and if allowed ordinary rates of transportation, can always be mined at a profit. As long as the Newcastle seams could be worked above water-level the average cost per ton was $1.10, but they never had the same advantages there as at Gilman, and most of their mining has been downward. $1.00 per ton is certainly high enough for Gilman after the entries are driven in sufficiently for large operations. If Mr. Whitworth succeeds in putting out the coal at $1.25 for the first six months, as he thinks he can, there need be no fear as to the future. [Sidenote: Prices of coal.] The selling price of coal on Puget Sound has ranged from $3.00 to $5.00 a long ton in former years, averaging $4.00--the price being the same for the product of all the different mines. Mr. Whitworth reports the price this winter at $6.50 a ton for all (including Newcastle), except Cedar River, which is $5.00. The distances from Puget Sound to Portland and to San Francisco, the principal markets, are: to San Francisco, between 800 and 900 miles by water; to Portland, 450 by water, and 150 by rail. There is now rail connection all the way to San Francisco. The average cost of sending coal to San Francisco, either from Puget Sound or Vancouver's Island, is $2.00. The usual price in San Francisco and Portland has been from $4.25 to $6.00 for coarse, and from $2.75 to $3.75 for small. On the 1st of February, 1888, the cargo price in San Francisco was--for Coos Bay coal, $9.50; Seattle coal, $10; South Prairie, $10; Nanaimo (domestic), $10; Nanaimo (steam), $12; Lehigh, $18; Cumberland, $12. These figures make it evident that a good margin of profit may be calculated on from the Gilman coal. Mr. Whitworth will not be able to get his bunkers up until he has his road in operation to the mines; but, with temporary chutes, he can load 100 tons a day from the time the road opens, say March 15th. In six weeks after beginning he expects to increase to 300 tons a day, and one month later he can make the output 600 tons a day. As the headings are driven in the product can be increased to almost any desired amount.