366 PROCEEDINGS OP THE CALIFORNIA 



Stations. Inter. Alts. Sea Line. 



Sea level at mean low tide 



Astoria 53 53 



Fort Vancouver 79 1 32 



Camp on mountain slope 5,820 5,952 



Summit of Mount Hood 5,273 11,225 



The computations are made with new tables which will shortly be published, 

 and which give results similar to Plantamour's formula, based on Regnault's 

 constants. They give results somewhat higher than if Guyot's tables had been 

 used, the latter giving the height of the summit, 11,185 feet. 



On our return I took a single observation at what is called " Government 

 Camp," about four miles below the camp on the mountain slope, and another at 

 a place called Stumpville, some eight miles further on the road towards Port- 

 land-. The results give for the former place 3,864 feet, and for the latter 1,830 

 feet above the sea level. 



The instruments used on the mountain have been returned in excellent order, 

 and compared with the one at Fort Vancouver with most satisfactory results. 



It may be asked : Why is it that the results here given differ so widely from 

 some previous estimates? Mount Hood is said to be, by Mitchell's School 

 Atlas, 18,361 feet, and the Rev. Geo. H. Atkinson with a party, ascended to 

 the summit in August of last year, boiled water with a spirit-lamp, found that 

 the thermometer read 180°, and therefore concludes the mountain is 17,600 feet, 

 and Government Camp 4,400 feet above the sea. The reason is, that the 

 instruments used are unreliable, and this method of computing the altitude 

 defective. With a boiling point apparatus (or thermo-barometer as it is called) 

 of the most approved kind, the results by boiling water are far inferior to those 

 by the cistern barometer ; but if the observations are made with a common ther- 

 mometer, with small spaces for degrees, as was the case in this instance, and the 

 instrument not protected from drafts of air, the results are utterly unreliable, 

 and therefore worse than worthless. 



Apart from the observations here described, there are other evidences to show 

 that the determination of the height of this mountain here given is not under- 

 estimated. Col. B. C. Smith, one of our party who reached the summit, had 

 this year ascended Mount Shasta, a mountain measured by Prof. Whitney to 

 be 14,440 feet. The Colonel states that he feels confident, from the compara- 

 tive ease with which he ascended Mount Hood, that it is of much less altitude 

 than Mount Shasta. 



On Mount Hood butterflies were found within a thousand feet of the summit. 

 Finally, Prof. Whitney and others, from rough triangulations, have estimated it 

 be about 12,000 feet. 



It is to be hoped that other parties with good instruments will take further 

 observations on this mountain. As the height of Fort Vancouver and Fort 

 Dalles are known, and as these are now permanent meteorological stations, 

 further observations on Mount Hood can be referred to one of these stations as 

 a base, and good results obtained. 



