the harbor about the same time on the same morning came near going on the rocks. The Pacific Mail Steamship Company has a rule that vessels must not enter or leave a harbor when fog prevails. On the morning in question the fog lifted for a few moments and then settled down again; but by 9 a. m., local time, the fog had dissipated. The rest of the day was clear and balmy and the water as smooth as a mill pond.

The vessel struck about 5.30 a. m., with the pilot and captain on the bridge, the first officer on the starboard side of the bridge listening for the bell, and the second officer at the telegraph. When the vessel struck, the captain blew the danger whistle, a long blast. Ordinary fog blasts (long enough to count six or seven) had been blown previously.

The details of the accident, particularly with reference to the whistles, the course steered, and the motion of the current, are given, because from such evidence as can be obtained at this writing it appears that even after the vessel struck the sound of the whistle was not heard plainly at Fort Point, not more than half a mile distant, where a lookout of the life-saving station was on duty and where a life-saving crew could have hurried to the rescue and probably reached the ship within five minutes, without doubt saving many of those whose lives were lost. There was also a sentry walking post within a short distance of the lookout. It is stated that some soldiers heard voices and also a whistle, but the evidence is very conflicting, and it seems improbable that if the long danger blast was clearly heard it should pass without notice and subsequent action.

The Weather Bureau records show that about the time of the accident a mongrel tule fog prevailed over the Bay of San Francisco. At Mount Tamalpais the weather was clear, with a wind of 13 miles per hour from the northwest. At San Francisco dense fog prevailed, with little, if any, wind. The wind vane at the Mills Building indicated a southwest wind blowing about 1 mile per hour. From 1 a. m. to 6 a. m. but 9 miles of wind were recorded.

When all is said and done it appears that the fog was the prime factor in causing the loss of the vessel. Owing to the aberration of the sound waves in the fog the pilot was unable to hear the fog signals from either Point Bonita or Lime Point to the north, or the tolling of the bell at Fort Point to the east and north. It has not, however, been shown that the bell was certainly ringing. The Lime Point whistle has great penetrative power. The fog bell at Fort Point is 40 feet above the water, and should be heard for at least a mile. It is supposed to be struck every ten seconds. It is a strange fact that in a paper upon the Fogs and Fog Signals of the Pacific Coast, by Ferdinand Lee Clark, published in 1888, there should occur this statement concerning the fog bell at Fort Point:

*

*

In point of fact it is said to be hardly ever heard except when too late to be of use. * If mariners depended upon its sound to tell them how near they were to the point, they would generally have no time after hearing it to clear the danger.

The loss of the Rio de Janeiro proves that the bell at Fort Point in its present position is sometimes of little value.

The temperature at the time of the accident was 50° F. at sea level and 52° at a height of 2,500 feet. The thickness of the fog probably did not exceed a few hundred feet; and, as indicated above, it was a land fog rather than a sea fog.

As a general thing the reflected sounds from Point Bonita and Lime Point are heard better on the south side of the channel. On the accompanying rough sketch of the channel the lines of natural reflection are drawn and also the zones of inaudibility.

It is not difficult to account for the failure of the echo of the ship's whistle from some portion of the northern shore, as the distance of the vessel from Point Diablo was too great. The sound waves from the fog whistle at Lime Point, however, should have been heard, and as the moderate southwest wind would tend to cause a deflection of the sound wave upward it is possible that while the sound was inaudible on the deck of the vessel it might have been heard by a lookout at the masthead.

The catastrophe furnishes a remarkable illustration of the utter helplessness of a vessel in fog, despite lights and fog whistles. It would seem that under such conditions nothing short of some method of fog dissipation will suffice.

It has occurred to the writer, although the suggestion may prove of no value in practice, that if a strong sound had been made under water by some automatic contrivance at either Lime Point or Point Diablo, and the Rio de Janeiro been provided with some suitable device rendering audible the sound wave through the water, the strong cross current would have facilitated the passage of the sound and a zone of audibility would have been established in the water, while in the atmosphere above the fog signals would have been inaudible.

The accompanying photographs, Plate VI, are submitted to show that to a certain degree the captain and the pilot were justified in assuming that they might soon run into areas free from fog. As a matter of fact on the day in question the fog soon disappeared and a delay of perhaps two hours would have prevented the accident. It should not be forgotten, however, that the captain was unwilling to enter the harbor during the fog Thursday night, and that the vessel remained at anchor for a period of nearly twelve hours and was thereby exposed in a large degree to the danger of collision.

THUNDERSTORMS.

It is sometimes stated that thunderstorms are exceedingly rare in California and that lightning is almost unknown along the coast. And it is generally believed that the Pacific coast, or at least the, southern half of it, is a region free from thunderstorms and the damage by lightning is practically an unknown quantity. In the eastern part of the United States considerable damage is done by thunderstorms between the months of April and September. In California thunderstorms may occur during any part of the year. In a discussion of 356 reports of thunderstorms in California from July, 1895, to August, 1896, we found that there were 3 dates in July on which storms occurred, 6 in August, 8 in September, 10 in October, none in November, 3 in December, 5 in January, 2 in February, 3 in March, 9 in April, 15 in May, 6 in June, 22 in July, and 17 in August.

Some of the storms covered very large areas and were quite generally reported, such, for example, as October 14-15, 1895; May 29 and August 28-29, 1896. Examining certain marine reports, it appears that on January 25, 1896, thunderstorms prevailed in the Pacific Ocean, and it is not surprising to find that a day or two later thunderstorms were reported in California. These storms apparently moved inland from the ocean. There is another class of storms, however, apparently connected with the general low-pressure movements from the southwest. A condition favorable for thunderstorms in the valley of the Colorado in July and August is frequently followed within ten or twenty hours by thunderstorms along the Sierra. The following table shows the distribution of thunderstorms in California during the year of 1895-96:

During the summer months in the great valleys and canyons of the eastern and southern portions of the State thunderstorms frequently occur during the afternoon and evening hours. John Muir, writing in the Atlantic Monthly for September, 1901, on the Big Trees, makes the following statement: "Most of the Sierra trees die of disease. Thus the magnificent silver firs are devoured by fungi, and comparatively few of them live to see their three hundredth birth year. But nothing hurts the Big Tree. I never saw one that was sick or showed the slightest sign of decay. It lives on through indefinite thousands of years, until burned, blown down, undermined, or shattered by some tremendous lightning stroke. No ordinary bolt ever seriously hurts Sequoia. In all my walks I have seen only one that was thus killed outright.

"Lightning, though rare in California lowlands, is common on the Sierra. Almost every day in June and July small thunderstorms refresh the main forest belt. Clouds like snowy mountains of marvelous beauty grow rapidly in the calm sky about midday and cast cooling shadows