April 6, 1893] 



NATURE 



535 



Severe Frost at Hongkong. 



The occurrence of severe frost at moderate elevations within 

 the Tropics must be rare. It seems worth while therefore to 

 place on record in the columns of Nature some portion at 

 least of an official report on the low temperature which (as was 

 slated in Nature last week) occurred at Hongkong between the 

 15th and 18th of January: 



Botanic Gardens, Hongkong, February 4, 1893. 



Sir,— The unprecedented cold weather which the region 

 about Hongkong was recently subjected to calls for some notice 

 by this department. Records of experiences of meteorological 

 phenomena such as we have just had besides being of passing 

 interest are so frequently of use in practical dealings with 

 various subjects that for this reason opportunities to record 

 unusual phenomena should not be neglected. It does not, how- 

 ever, come within the province of this department to go much 

 further into the meteorological aspects of the subject than is 

 demanded in connection with its injurious effects on vegetation. 



(2) After a period of ordinary Hongkong dry, cool weather 

 rain fell on January 13, and continued daily up to the l6th 

 instant. In the gardens, at 300 feet above sea level, the follow- 

 ing quantities of rain were registered with a Glaisher's rain 

 ^auge :— 



January 14 



M 15 

 „ 16 



.14 

 .35 

 .46 

 •45 



(3) On the 15th instant the temperature fell in the afternoon 

 to 39° F., at 350 feet above sea level. On the l6th, at 

 -9 a.m., it stood at 35°. On the 17th the thermometer stood 

 at 31° at 9 a.m., which was the lowest temperature observed 

 at the Gardens. During this period the sky was overcast 

 except for a short time about noon on the 17th, but on the 

 morning of the i8th it was clear and the sun shone brightly 

 throughout the day, the temperature having risen to 43" at 

 4 p.m. 



(4) Unfortunately there are no official records of temperature 

 at Victoria Peak, 181 8 feet above sea level, but, by such infor- 

 mation as could be obtained from private observers in the hill 

 district and observations made here, it seems that the tempera- 

 ture must have fallen at the summit to about 25° or 24° F. 



(5) On the river at Canton, and between this port and that 

 place, low temperatures were recorded in the reports of the 

 steamships Powan and Honam. They gave — 



January 16 at I A.M. 23° about 28 miles below Canton. 

 ,, ,, at 10 A.M. 26° about 25 miles from Hongkong. 

 ,, ,, at 1 P.M. 25° at Canton. • 

 „ 18 at 10 A.M. 28° about 25 miles from Hongkong. 



I am indebted to the Office of the Hongkong, Canton, and 

 Macao Steamboat Company for these returns. 



(6) On the peninsula of Kowloon the cold appears to have 

 been greater than in Hongkong ; ice was seen on pools of water 

 in the roads within fifty feet of sea-level, and at the Kowloon 

 Docks ice was observed at the bottom, thirty feet below sea- 

 level, of an empty dock. 



(7) In the harbour the rigging of ships was coated with ice. 



(8) Since the records began in 1884 the temperature has 

 not fallen, until now, at the observatory, below 40° F. I 

 remember on one occasion, I think about seventeen years 

 ago, ice was found at Victoria Peak, but there is no record 

 within my experience, which extends back nearly twenty-two 

 years, when ice was observed below 1700 feet altitude. 



(9) The continued low temperature combined with fall of rain 

 from an apparently warmer stratum of air above, resulted in the 

 formation of ice varying in quantity from a thin coating on the 

 upper leaves of pine trees growing at 300 feet above sea level, 

 to a thick encasement of perfectly transparent solid ice of 5^ 

 inches in circumference on the blades and bents of grass at the, 

 summit of Victoria Peak. The grass bents themselves, which 

 were the foundation on which the ice accumulated, were not 

 more than an eighth of an inch in diameter, yet the formation of 

 ice was so gradual that with the enormous accumulation of ice, 

 which became its own support, the bents retained their natural 

 upright, or but slightly pendent position. These large accumu- 

 lations of ice were on the windward side of the hill where rain 



NO. 1223, VOL. 47] 



drifted, but even on the lee side the average coating of ice was 

 about 3 inches in circumference. 



(10) Evergreen shrubs and trees carried on their leaves solid 

 coverings of ice % of an inch in thickness. The great weight of 

 this ice caused the blanches of trees to assume a pendent form, 

 the strain in many cases causing the limbs to snap off with a 

 crash. All vegetation throughout the hill regions of the Colony 

 was thus covered with ice, as were also most other objects. 

 Telegraph and telephone wires from Victoria Gap upwards 

 were covered with ice \ of an inch in thickness, and, in 

 addition, carried icicles as much as three inches in length as 

 close as they could be packed side by side. This caused many 

 of the telephone wires to break, and the iron post at Victoria 

 Gap which supported them was snapped off a few inches above 

 the ground. 



(11) The windward sides of the walls of the look-out house at 

 the Peak were from top to bottom covered with perfectly trans 

 parent ice \ of an inch in thickness. 



(12) All the hills on the mainland and Lantao island were 

 likewise white with ice, one of the hills (3147 feet) of Lantao 

 having what appeared to be snow for some few hundreds of feet 

 down from its summit. As early as the evening of January 15 

 the summit of Taimoshan (about 3300 feet) on the mainland 

 had assumed a whitish appearance, presumably from ice or 

 snow. 



(13) The effect of the extremely low temperature on vegeta- 

 tion has been disastrous. 



(15) The damage in the gardens consist chiefly in the injury or 

 destructionof leaves, but some plants are quite killed, these being 

 natives of much warmer regions than Hongkong. Many of the 

 decorative plants which were not killed will be months before 

 they can regain their ornamental appearance. 



(16) Every possible precaution was adopted to minimise the 

 effect of the cold. The plant-houses, which are provided with 

 screens merely to produce shade, were all matted in and the 

 roofs covered with straw. In spite of these precautions, how- 

 ever, many plants suffered very severely. Of ferns in the houses 

 Polypodhwt HeracUum and Adianium tetradactylon suffered 

 most, other kinds being but little affected. 



(17) In the orchid-house, which was covered with mats and 

 straw, all our best orchids have suffered very greatly, many 

 being entirely killed while others were so much injured that, 

 even if they survive, it may be some years before they regain 

 their previous luxuriant state. A healthy plant, received from 

 Calcutta several years ago, of Dendrobium aggregatum, is 

 apparently killed, while plants of the same species growing by 

 its side, and also others on trees where they had no shelter, 

 which I collected ten years ago on the Lo-fau mountains, about 

 sixty miles from Canton, have escaped unharmed. This seems 

 to show the capability of the plant in adapting itself to colder 

 regions than it is generally found in. 



(19) The highest point of the Gardens is 320 feet above sea- 

 level, the lowest part 175 feet. Some plants of the same kinds 

 which were damaged at the upper portions were uninjured at 

 the lower parts of the Gardens. 



(20) Of exotic trees planted on the hills Albizzia Lebbek, 

 Aleurites triloba (candle-nut-tree) and Eugenia Jambos (the 

 rose-apple-tree) had all their leaves killed at and upwards of 

 600 feet above sea-level. Trees of the rose-apple at about 800 

 feet altitude haVe been entirely killed. 



(21) At 600 feet altitude indigenous plants began to be 

 affected, the injuries increasing with higher altitude until at 

 about 900 feet when the extreme limit of low temperature which 

 some plants could bear was reached, and death ensued. Most 

 of these are tropical plants of which Hongkong, Formosa, the 

 Luchu Islands in the Far East, and Sikkim and Himalaya in 

 India are the northern limits of the geographical area from 

 which they have been recorded. Of the plants killed or injured, 

 Ficus Harlandi, Benth., Gordonia anomala, Spreng., and 

 Garcinia oblongifolia. Champ, are known only from Hongkong. 

 Although many of our indigenous plants have not been yet 

 discovered elsewhere, it is to be expected that when China is 

 better known they will be found over a larger area than the 

 restricted one of this island. The fact of the above named 

 plants having succumbed to the late frost indicates that when 

 jhey are discovered elsewhere they will be found southward of 

 Hongkong. 



(22) Considerable damage to vegetation seems to have been 

 caused about Canton, where the alluvial lands are highly cuiti- 



