584 A NATURALIST IN THE PACIFIC 



the winds is insufficient for the purpose of obtaining any definite notion of 

 the air-currents at this elevation (13,600 feet). It is to close observation 

 of the clouds that we must look for data of importance. 



The Clouds. — The clouds on the summit of Mauna Loa were an un- 

 ending source of interest to me, and I will give briefly the results of my 

 observations. The highest clouds were wispy cirri, often arranged as in a 

 mackerel sky, and evidently at a great altitude. They were only observed 

 on four or five days. (The lower clouds are indicated in the accompany- 

 ing diagram.) Below them and at no great height above the mountain 

 were to be not infrequently observed isolated woolly clouds that were 

 carried in a few minutes -across the sky and had a brief existence, often 

 forming and melting away as one gazed at them. Next, there was a heavy 

 bank of cumulus, which formed on the south-west slope near the top of 

 the mountain, from which lines of cloud extended along each flank. 

 Lowest of all was a broad belt, or rather a sea, of cumulus that was 

 developed on both sides of the mountain about one-third way down its 

 slopes, and during the day-time isolated the peak from the world below. 

 It is with the last two cloud formations that we are most concerned, and 



I will first describe the sea of cumulus. 



The sea of cumulus, as in the case of similar cloud-formations of most 

 other isolated mountains, when viewed from above, as from the mountain- 

 top, presents a cloud-field of dazzling whiteness, sparkling in the sun. 

 Seen from below, as from the coast, it has the dark lowering appearance of 

 the rain-cloud and indicates the rain-belt. Disappearing during the night, 

 this broad belt begins to form again between 8 and 9 a.m., and by 10 or 



II a.m. the lower regions are completely hidden and the mountain's 

 summit, cut off from the world, rises above the level of the sea of clouds 

 like an island in an Arctic ocean. As the day progresses the clouds 

 become more compact and dense. The usual altitude of this broad belt 

 of cloud is between 7,000 and 8,000 feet. This level is indicated by the 

 burying of the Kohala mountains, which rise to a height of 5,500 feet in 

 the distant north-west corner of the island, and by the usual emergence of 

 the highest summit of Hualalai, which rises, still nearer, to an elevation of 

 8,275 feet. On some days, however, it attains a height of nearly 9,000 

 feet. On such occasions the highest peak of Hualalai kept reappearing 

 and disappearing during the day, but the distant summit of Haleakala in 

 East Maui, 10,032 feet in elevation and 80 miles away, was always visible. 



Words fail to describe the magnificent aspect of this sea of cloud which 

 shuts off the spectator from the world below. From the summit of the 

 mountain he gazes down on its surface Ut up by a sun shining in a typically 

 cloudless sky. At one time it appears as an undulating Arctic land covered 

 with snow of dazzling whiteness. At another time it looks like a hum- 

 mocky frozen Polar sea sparkling in the sunshine. Through occasional 

 rifts, however, one can discern a dark dismal region of mist and rain-cloud 

 beneath. Miss Bird, who passed a night on the summit in June, 1874, 



