GEOLOGY AND TOP(^GRAPIIY OF IIA^YAII. 155 



visit. An account of the ascent made at that time was recorded in Archiliald 

 Mcnzie's journal, in 1794, and remained unpublished until brought to light 

 through the researches of Prof. Hitchcock and printed for the first time in 

 Thrum's Annual for 1908. Mr. Menzie calculated the height of the mountain 

 by use of the barometer without corrections for the variations in temperature '- 

 and made it but forty-one feet less than the present accepted altitude. From the 

 time of Menzie 's ascent to the present the mountain has been under almost con- 

 stant observation, and many parties of competent observers have attained the 

 summit. Its extensive and interesting history has been fully recorded and com- 

 piled in two elaborate monographs, one by Prof. Hitchcock and the other by 

 Dr. Brigham, both appearing in 1909. To these works the reader is referred 

 for detailed accounts of the long series of eruptions, the bare enumeration of 

 wliich are almost beyond the scope of this chapter. 



History of the Eruptions of ]Mauna Loa. 



However, it is of interest to know that eruptions were reported on Mauua 

 lioa in 1780 and again in 1803; the first fully recorded eniption occurred in 

 1832, and in June of that year ]\Iauna Loa is reported, by the Rev. Joxeph 

 Goodrich, to have ejected lava from several places in the side of the mountain, 

 presumably some little distance below the summit. From that time until the 

 last eruptive flow ^^ the lava has always issued from the weak places in the side 

 of the moinitain, though the caldera at the summit has on numerous occasions 

 become active, forming a lake of lava without flows taking place. 



Of the fifteen eruptions resulting in flows that have occurred on Hawaii 

 within the last one hundred years, twelve have had Mauna Loa as their source. 

 The eruption of 1843 was presaged by activity in the crater of Mokuaweoweo 

 but after a few hours the fire died down in the crater and reappeared on January 

 10, 1843, in two places on the northeastern shoulder of the mountain, at about 

 11,000 feet elevation ; from these, lava ran in a broad sheet down the side of 

 the mountain for about sixteen miles directly towards the peak of Mauna Kea, 

 flowing continuousl.y for a period of four weeks. In the saddle between the two 

 mountains the .stream widened out and spread over the plain, being four and a 

 half miles across in the widest part. One branch extended a considerable 

 distance down towards Waimea on the west, evidently uniting with a fni'iner 

 eruption known as the Keamuku flow. 



The flow of 1851, beginning on August 8th, was announced by a remarkably 

 brilliant display accompanied by detonations in the summit crater. This flow is 

 said to have occurred from an opening on the we.st side of the mountain about 

 1,000 feet below the summit a"nd to have extended for ten miles westerly in the 

 direction of Kealakekua. It lasted only about four days, and is not connnonly 

 shown on maps. 



In Ihe following year, on February 17, 1852, light was again seen on the 

 sunnuit, and within a short time lava broke out on the northern slojie of the 



'^Wliich would reduce the altitude, as given by him. hy iihnut seventy feet. '»In 1907. 



