METEOROLOGY OF THE FIELD EXPLORED. 135 



or perhaps a little above, the head of his horse, and he got the impression from them that there 

 was more snow than usual. 



I have no question that there are exceptional winters, when the snow may for short distances 

 considerably exceed the depth found this winter. But it will require the combination of some 

 two months weather much colder, and moisture more excessive, than the average. Thus the last 

 two winters have each given only one cold month January last winter, and February the winter 

 before. About the same quantity of rain and snow fell each month, viz: eight inches and a 

 fraction; much of it was no doubt deposited in the pass in snow. I am of opinion, however, that 

 even in these months some rain fell in the pass, and that in the remaining months of these years 

 it fell principally in rain. I am aware that the quantity of moisture at Steilacoom is not the 

 measure at the pass, where it must be much less. These observations are conclusive, however, 

 relatively, as they determine the quantity of moisture deposited in the sound, to which the moist 

 ure in the pass must have definite relation. It will be interesting to continue these observations 

 through a term of successive years. 



The experience of Fort Ben ton and St. Mary s valley is full of significance and instruction. 

 I am assured by Mr. Pambrun, the chief clerk in charge of the Wallah- Wallah post, that his father 

 took a band of horses through the Nahchess Pass about Christmas, some years since, and I inter 

 rogated one of the employes at the post, who actually accompanied Mr. Pambrun, sr., on the 

 occasion. I am informed by respectable gentlemen on the sound, that it is no uncommon thing 

 f^r the Indians to cross the Snoqualme Pass with horses in mid-winter. At all events, the In 

 dians who accompanied Mr. Tinkham in January, made their arrangements to recross the pass in 

 February. They cached their snow-shoes at the upper end of iNook-noo lake, eighteen miles 

 west of the summit, thus showing that they did not expect much increase of snow, and they de 

 sired to take the foot-trail referred to by Captain McClellan, assuring him there would be less 

 snow than in the usual horse-trail. Moreover, there is every reason to believe that the snow was 

 in unusual quantities in the cascades the last year. It is well known that a much larger quantity 

 of snow was deposited on the shores of Puget sound. Careful observations of the temperature, 

 and of the amount of water falling in rain and snow, have been taken for a consecutive period 

 of five years at Fort Steilacoom, and the result has been that more water was deposited the last 

 year than the average of five preceding, but that more must have been deposited in snow. A com 

 parison of the three winter months, for the past five winters, shows, at Fort Steilacoom, a deposit 

 of 20.68 inches the last winter, against 20.22, 20.86, 19.39, and 22.10, for four previous win 

 ters: adding the month of November, it shows 39.09 against 26.39, 23.88, 24.53, and 31.52 ; or 

 throwing out February, in order to bring the comparison as near as practicable to Mr. Tinkham s 

 crossing of the pass, we have 31.52 this year against 23.15, 18.45, 23.06, and 26.69. The av 

 erage temperature of the three winter months is 38.3 for this year, against 37.3, 43, 39.6, and 

 37.1, of previous years ; and for the three months, November, December, and January, we have 

 40.1 this year, against 40.3, 44.1, 40, and 40, of previous years. The moisture is in great excess, 

 nearly fifty per cent., and the temperature is slightly below the average. In November last the 

 mean temperature was but 1%- of a degree greater than in December. It is true that in February of 

 this year there was nearly as much moisture deposited as in January, and the temperature was 

 only 1.3 above the average of the three months. It is greater than that of January by 9, and 

 less than the average of November and December 5. 3. A greater proportion of snow neces 

 sarily fell in that month than in November and December. Moreover, the experience of the 

 survey of Clark s fork corroborates this. 



Excepting for about six or seven miles, the Snoqualme Pass is at a much less average elevation 

 than the route from Thompson s prairie to the Cceur d Alene prairie ; and being in close vicinity 

 to the waters of the sound, the temperature must be higher. The average temperature down 

 Clark s fork, where the snow was met with, from Thompson s prairie to Pend d Oreille lake, 

 and from the crossing of Clark s fork to the Cceur d Alene prairie, was about 32 j whereas 



