LETTER TO THE SECRETARY OF WAR. 631 
on the 20th of January. To within twelve miles of this camp I had not found the snow to have 
an average depth greater than two and a half feet—a dry, cold snow ; but beyond this the snow 
had greatly increased in depth, varying from four to six feet, and at the night camp some four 
feet deep. The lakes were frozen and covered with snow, and their smooth, even surfaces 
afforded easy travelling for snow-shoes. Some five miles distant from this camp, in the summit 
of the pass, is what in the depth of the snow I took to be a small, open marsh, but have since 
learned is a small pond, whose waters are turned on either slope of the divide. Although, with 
the disadvantages under which I was placed, I could not examine the pass with the care I de- 
sired, and with which I felt confident it had been examined by the other parties to whom you had 
committed the special exploration of the passage of the Cascade range, I was still satisfied that 
it afforded fair facilities both in its ascent and descent for a wagon and railroad—either with the 
use of eighty-feet grades for a limited number of miles and a short tunnel, or with a longer tunnel 
and easy grades. 
Wishing to know the real difficulty to be apprehended from the passage of these mountains in 
the winter season by railroad trains, I gave particular attention to the measurement and exami- 
nation of the snows on the route. From Kitch-e-lus lake to the summit, some five miles, and 
where occurs the deepest snow, the average measurement was about six feet, but frequently 
running as high as seven feet. In a storm occurring on the night of the 20th, about one and a 
half foot of this depth was deposited—a very light, dry snow; so light as to afford no support to 
our snow-shoes, and making our progress slow and laborious. The whole of the snow was very 
light and dry, deposited in successive layers of from one to two feet, and for the greater part of 
the route had lain undisturbed since their fall—every twig and bush bowing under their bulky 
burden. These snows present little obstruction to removal in comparison with the compact, 
drifted snows of the Atlantic States, and would cause very little detention to the passage of 
trains. Passing on to the western slope of the Cascades, the snow rapidly disappears; fourteen 
miles from the summit there was but eight inches of snow, and thence it gradually fades away 
as the approach is made to the shores of the sound. 
It should be borne in mind that this examination was made in mid-winter, from the 20th to 
the 25th of January, and in a winter known to be one of unusual cold, and that the accumulated 
snows of the winter were but about six feet in their greatest depth, and this depth only covers some 
half dozen miles of the route, and embracing, too, that portion of the route which will be tun- 
nelled and protected. Descending, the snow rapidly decreases on both slopes of the mountain, 
on the eastern side about thirty-five miles from the summit, amounting to but from one and a 
half to two feet in depth, and on the western side fading away until in the short distance of four- 
teen miles it is only eight inches deep. 
Without giving the details of the remainder of my journey to the sea-board, which in a more 
extended report may be noticed, I reached the vicinity of Seattle, under the guidance of Indians, 
on the night of January 27, tracing a very excellent railroad connexion from the valley of the 
Snoqualme to that commodious and beautiful harbor. 
I am, sir, very respectfully, your obedient servant, 
A. W. TINKHAM. 
His Excellency Gov. Isaac I. Stevens, 
Chief of the Northern Pacific Railroad Survey. 
Orrice NortHern Pactric Ratroap ExpLoraTIon AND SuRVEY, 
Olympia, Washington Territory, February 13, 1854. 
Sir: I have received your instructions of December 1, 1853, disapproving of my arrangements 
for a winter examination of the mountain passes, and for a resumption of the work should Con- 
gress make an appropriation, and directing me to bring my operations to a close in accordance 
with the original instructions. 
