MEETINGS 2004

245th Meeting - Tuesday, March 9th 2004 

"The Expedition Mekong 2002 in Perspective"

A talk by Reinhard Hohler

Present: Julie Ach, Gisella Anselmi, Hans Baumann, Michael Bauwens, Robert M. Boer, Hanna Brandli, Steve Brooks, John Cadet, Kay Calavan, Mike Calavan, Guy Cardinal, Jim Campion, Penkhae Camsa, Etienne Daniels, Bernard D. Davis, Seraphina Denault, Martine Gautlier, Jim Goodman, Guy Horton, Otome Hutheesing, Ken Kampe, Onsri Khamnoi, Omtip Mekrugsawanich, Richard Melville, Richard Nelson-Jones, Ray Nolan, Jacques Op de Laak, Hans Penth, Mengnoi Penth, Somkuan Piboonrat, Lucas Postma, Horst Schnarder, Gert Slambrouck, David Steane, Bob Stratton, Carol Stratton, Bob Tucker, Alysha Wood. An audience of 38. 

Introduction

"Expedition Mekong 2002'' was co-organized by the Brooker Group and Diethelm Travel. The expedition was from November 2^nd to 17^th 2002 and covered nearly 3,000 km of the Mekong river from Simao Port in Yunnan to its delta in the southern part of Vietnam.
 
Profile of Expedition Mekong's tour director Mr. Reinhard Hohler:
Reinhard Hohler is an experienced tour director and media travel consultant in the Greater Mekong Sub-Region. He was born in Karlsruhe, a port on Europe's Rhine River. After studying geology in his hometown and ethnology at Heidelberg University, Mr. Hohler moved to Thailand in 1987. He has led more than 90 study tours, mainly in Thailand, Myanmar, Cambodia, Laos, Vietnam, Yunnan, Hainan, Hong Kong, Malaysia and Singapore. He also co-authored a book about Yunnan and a documentary about the Emerald Buddha in Bangkok. Mr. Hohler is a life member of The Siam Society and currently working on a project about German explorer Dr. Adolf Bastian's travelogue of Southeast Asia in the early 1860s. Presently, Mr. Hohler lives in Chiang Mai with his wife and daughter.
For further information, please contact Reinhard Hohler by e-mail: sara@cmnet.co.th

Extracts from the Logbook of Expedition Mekong 2002 by Reinhard Hohler, selected by your convenor, Brian Hubbard.

Nov 2^nd Saturday. Bangkok Airways’ flight PG 640 from Bangkok to Jinghong in the south of China. The three organizers of Expedition Mekong 2002 were on board the flight. From Switzerland, Armin Schoch, group general manager of Diethelm Travel Bangkok, who provided the logistic support to the expedition. From England, Dr. Peter Brimble, president of the Policy Research Division of the Brooker Group in Bangkok, whose idea it was to cruise along the mighty Mekong from Yunnan to the delta in Vietnam. And from American, Dr. David Oldfield, Brooker’s executive vice president, who saw the expedition as a revival of the more than century-old French River Expedition which set off from Saigon on June1866. Also on board were Jinda Oudomsin, our interpreter from Laos as the vital link between the Chinese crew of the Shanghai-built hovercraft and the English-speaking command, and one of our passengers, Belgian Cyrillus Van Tilborgh, whose intention it was to write a book about the expedition.

At Chiang Mai International Airport, German tour director Reinhard Hohler joined the expedition to be responsible for disseminating relevant information en route during this once-in-a-lifetime epic voyage through the heart of Southeast Asia.

 At 16.00 we landed on the new Xishuangbanna International Airport in Jinghong and were welcomed by Isa Dannart, the representative of Diethelm Travel Yunnan. It was only a short transfer to the beautiful Tai Garden Hotel, which is the only four star hotel in Jinghong, the industrial capital of Xishuangbanna Dai Nationality Autonomous Prefecture.

In the lobby of the hotel we met with another passenger, American Rodney Soensken, who arrived in Jinghong via Kunming.  We also met Ni Shao Zhi, the Chinese owner of the hovercraft, which is aptly named “The Golden Quadrangle”.

Nov 3^rd Sunday. At 7.00 we had breakfast in the hotel and then departed by bus from Jinghong to Simao, 165 km. along a paved mountain road. We crossed the newly built bridge over the Lancangjiang River and had a scenic drive through the countryside.

Upon reaching Simao, at 15.30, we celebrated the start of the Expedition Mekong 2002 with glasses of champagne on board the hovercraft.

At 16.00 we left the Simao River Port by hovercraft. The Lancang-Mekong River is one of the largest in the world, flowing for 4,200 km. through six countries: China, Myanmar, Laos, Thailand, Cambodia and Vietnam. From its source high up in Qinghai Province of Western China called Dza Chu, meaning “rock water”, the Upper Mekong flows through narrow gorges through the western part of Yunnan along elevated chains of mountains side by side with the Yangzi in the east and the Nujiang-Salween in the west. The longest section of the Mekong Basin in China is steep and the tributaries are short. The snowmelt in the Himalayan Mountains leads to a spring peak in the upper reaches. One of the biggest lakes of Yunnan, Erhai Lake in Dali, has its outflow into the Mekong. Simao Port is currently the northernmost point on the river from where commercial navigation is possible.

The Lancang-Mekong River has a total fall of 5,500 metres, of which 5,000 metres are within China. As most of the hydro-electrical projects are planned on the mainstream with a cascade development of eight dams, it is obvious that one of the bitter consequences of dam construction for power generation, water supply and flood control is the disruption of the ecosystem and the collapse of the fish populations. The river is the life-blood of the people living along its banks, supplying water for them and their crops, and also serving as a means of transportation and travel.

While China has joined the “Economic Quadrangle” with Myanmar, Laos and Thailand, it is not a member of the Mekong River Commission, with Vietnam, Cambodia, Laos and Thailand.

Skimming over sandbanks and whirlpools we arrived at Jinghong’s old bridge, built in 1960, at 18.00.  We went to a rustic Dai family restaurant to have sticky pineapple rice and local wine, and then to bed early to be ready for tomorrow’s long journey down the river to Thailand.

Nov 4^th Monday. At 6.00 a shrill morning call woke us up to make our long-awaited dream come true. The first-ever hovercraft expedition will take us through China to the middle and lower parts of the Mekong. According to some Chinese maps, the whole of the river is navigable except for some 30 km in the southern part of Laos, where the Khone Falls are a barrier for any kind of boat. It will be there that the hovercraft will be lifted out of the water by crane and transported around the waterfalls on a flatbed trailer.

The 8 ton hovercraft can travel 40km/h and accommodates up to 20 passengers in addition to a crew of four: Zhang Jianhua was our first captain of the hovercraft and Cui Xincheng was the second captain. Yang Chunhong was the engineer, while Luo Xiaoyong acted as the cabin boy.

At 6.30, our six foreign explorers with our Lao interpreter left the Tai Garden Hotel to the new Jinghong Port Authority Building. After the immigration inspection procedure, a local television team approached us to interview Armin Schoch, our expedition leader. Finally, at 7.45, Mister Ma, the head of the Port Authority, waved us farewell as our hovercraft slipped slowly away. Today’s journey from Jinghong to Chiang Saen in Thailand will be 340 km., one of the longest of the entire expedition.

At Guan Lei, on the Chinese side of the river, the Chinese had to show their passports to leave their country. At 10.00 we continued down the river and stopped at the “Green Triangle”, where a triangular stone pillar marks the border of China, Myanmar and Laos at the mouth of the Nan La River. From here on, the so-called Middle Mekong, the river is wild and untamed, forming the international border between Myanmar in the west and Laos in the east.

From 10.45-11.30, we stopped in Hua Khong in Luang Nam Tha Province of Laos to get our passports stamped in, but the officials sent us down the river to Xieng Kok instead. In Xieng Kok, we met three Lao nationals: Mixai Houmpheng, our guide from Diethelm Travel Laos, and Saleumsak Boukhasit and Visith Sisa-ad, officials from the National Tourism Authority of Laos and the Prime Minister’s Office, who accompanied us all the way down to the Cambodian border. We left Xieng Kok at 15.30. 

At 18.00 we passed the last Laotian outpost Xieng Mom and reached the Golden Triangle Paradise Casino, on the Myanmar side of the Mekong, at sunset. We arrived at the modern pier of the walled town of Chiang Saen after sunset and after an eight hours cruise. Wanida Sathit, the local manager of Diethelm Travel, took care of the immigration procedure and the transfer to the scenic Baan Boran Hotel, situated on the Thai side of the “Golden Triangle”.

Nov 5^th Tuesday. No morning call this morning. Time to have breakfast in the Yuan Lue Lao Restaurant until our departure from the hotel at 10.00.

After leaving the Baan Boran Hotel we returned to the pier in Chiang Saen and departed at 11.00 to Ban Houay Xai in Bo Keo Province of Laos.

At 12.00 we reached Ban Houay Xai opposite the Thai town of Chiang Khong and needed just 60 minutes for our second entry into Laos.

At 16.00 we reached the crowded river port of Pakbeng, 190 kilometers from Chiang Saen.

Leaving our hovercraft after today’s four-hour cruise, we had a surprise welcome by a group of attractive Lao girls, who were smiling and giving out flowers. We were cordially invited to the Diethelm-owned Villa Salikha to drink Beer Lao and “Lao Lao”, the local rice liquor, in the company of the nai amphoe and other officials from the small district town.

At 17.00 we checked in at the “Luang Say” Lodge, managed by Singhalese Moazzem Hossain. He had arranged a traditional “baci” ceremony at 18.30 to welcome the members of the Expedition Mekong before the Lao style dinner with minced duck meat, papaya salad and sticky rice.

Nov 6^th Wednesday. Today’s journey will be only 160 km., so we had enough time in the morning to go out to meet some school children in their neat uniforms on the way to the local market, where we marveled at grilled bamboo rats and frogs, offered as food to the unwary travelers. It was good to arrange an American breakfast in the hotel before the departure at 9.00.

At 9.15 we continued down the river towards Luang Prabang, the former royal city and the next destination of our itinerary in Laos.

At 10.45 we arrived on a huge sandbank, towered above by a big Black Hmong village named Khok Ek on the right side of the river, where we were quickly surrounded by curious children and elderly people in their traditional costumes.

At 14.30 we crossed the Mekong River to the caves of Pak Ou, which are located within a steep limestone rock-cliff, rising vertically from the waters of the Mekong at the point where it meets with the Nam Ou River, 30 km. north of Luang Prabang.

At 15.30, we left the caves, went back to the hovercraft and proceeded to Luang Prabang. At 16.00 we reached the confluence of the Nam Khan and landed at the nearby pier of Wat Xieng Thong, ending a four-hour cruise. 

At Wat Xieng Thong we attended a welcome ceremony, arranged by Madame Vayakone Bodhisane, managing director of Diethelm Travel Laos, in front of the ordination hall of the temple with its multi-tiered roof sweeping elegantly almost to the ground. Some very colorfully dressed dancers gave a performance with scenes from the Ramayana, an Indian epic that is more than 2000 years old.

After the welcome ceremony we were transferred to the Pansea Phuvao Hotel, managed by French national Nicolas Pillet and room division manager Benjamin Barthe. We checked in at 17.30 and two hours later sat down to enjoy a special three-course dinner.               

Nov 7^th Thursday. After a good night’s sleep we spent the day exploring Luang Prabang and its environs. In the evening we welcomed our Chinese guest Wang Xiaogang, an ecology and culture expert from Yunnan to join our expedition to Ho Chi Minh City.

Nov 8^th Friday. As we had 470 km. before us from Luang Prabang to Vientiane, we left our hotel at 5.00 a.m. and departed on the hovercraft at 6.00 a.m. into a foggy landscape of mountains, clouds and fairies.

Heading south from Luang Prabang, we passed Tha Deua, an important ferry point at the Mekong to reach Sayabouri. This still densely forested area is the home of the elusive Mlabri, a group of people who live as hunter-gatherers deep in the jungle. There are not more than 200 left on both sides of the border, still living a prehistoric life-style.

At 10.00 the mountains became lower and lower. We had reached Vientiane Province on the left side of the river. An hour later, we arrived in Pak Lai to refuel our hovercraft.

At 15.00 we passed the Lao custom station of Ban Vang.

Finally, at 17.00 we reached the industrial port of Vientiane, four km. south of the town. We were altogether ten hours on the river.

After the transfer to the first international four-star hotel in the capital, Accor’s Novotel, general manager Bernado Godinez gave us a heartly welcome. Also, we met another passenger, Chinese Humphrey Wou, who lives in America.

Nov 9^th Saturday. At 6.00, there was our morning call to have a buffet breakfast in the coffee shop and to leave the hotel at 7.00. At 7.45 we left the port of Vientiane.  

At 16.45 we finally arrived at Thakhek in Khammouan Province of Laos, near a chain of characteristic limestone hills just across from the Thai provincial town of Nakhon Phanom.  After getting our passports stamped, we were invited by the chief of the office of the local tourism authority to another “baci” ceremony for leaving the country.

We crossed the river to the Thai immigration officers, who had waited for us since 18.00. For today’s 370 km. we needed nine hours with the hovercraft. We had a minibus transfer to the Nakhon Phanom River View Hotel, where we met with the invited travel writer from Bangkok, British Paul Davies, representing Travel Weekly in Singapore, who intended to go with us to Cambodia.

Nov 10^th Sunday. It will be a long day again. That was the first thought that came up when we left the hotel after breakfast at 7.30. Our destination was Khong Chiam at the confluence of the Mun River with the Mekong in Ubon Ratchathani Province, 300 km. away. Despite the Mekong River forming the border between Laos and Thailand, for today’s entire journey we technically remained in Thailand.

At 8.15 we left the port to pass Wat Phra That Sikhotabong on the Lao side in the morning light.

At 11.00 we passed the dangerous rapids of Kaeng Ka Bao, just before the provincial town of Mukdahan opposite the Laotian town of Savannakhet, which is the largest town in the south of Laos.

After passing the rapids of Kaeng Tang Lang in Amnat Charoen Province we reached Khemarat in Ubon Ratchathani, where we refueled, at 13.00

At 13.45 we left the pier in Khemarat and passed a series of rapids and huge expanses of sandstone rocks in the river.

At 17.00 we reached Pha Taem National Park. Pha Taem is a high cliff overlooking the Mekong valley down below.

Most of the passengers left the hovercraft at a small sandbank and hurried into a waiting minibus to reach Tohsang Resort in Khong Chiam. Dr. Brimble’s wife and son had to rent a pickup car to reach the airport in Ubon Ratchathani to fly back to Bangkok on the same evening. Armin Schoch and the crew continued in the hovercraft to the hotel pier in the dark.

Nov 11^th Monday. As some of the passengers wanted to see the prehistoric rock paintings, we arranged breakfast at 6.00 at the Terrace Bar surrounded by a lush garden decorated with Khmer-style sculptures.

9.00 With our passport stamped in at the land border of Chong Mek, with the help of Miss Phuvieng, the local Diethelm guide from Laos, we crossed into Laos for the third time.

At 11.00 we reached Champasak on the western bank of the Mekong, an independent kingdom since the beginning of the 18th century, alongside Vientiane and Luang Prabang.

At 12.30 we had lunch in the hotel restaurant of Sala Wat Phu, where we met with Peter Wennberg from the newsmagazine “Good Morning Chiang Mai”. He came with us to photograph the hovercraft transfer operation at the Khone Falls.

At 16.15 we reached Ban Hat on the east bank of the river opposite the island of Don Khong.  At this most southwestern tip of Laos along the Cambodian border, the Mekong reaches its maximum breadth of 8 km. at the end of the rainy season.

We immediately started to lift out the heavy hovercraft with the help of a crane brought in from Bangkok. The operation lasted more than two hours because the hovercraft slipped off the pier several times and had to be drawn by ropes to the crane to be lifted on the waiting flatbed trailer, to the cheers of many spectators.

At 18.30 we boarded the tour bus and took the ferryboat to Don Khong to check in at the Villa Muang Khong Hotel. There we had a local dinner and feasted until midnight.

Nov 12^th Tuesday. At 7.30 we had our breakfast and started our sightseeing trip in Si Phan Don.

Riding in the bus, we left the hotel at 8.00 to cross the Mekong by ferryboat again. On the other side, the trailer with the hovercraft had just left Ban Hat back to Highway 13, heading south to Veun Kham, 30 kilometers to the Cambodian border.

The trailer with the hovercraft followed a specially widened side road some four km. back to the Mekong and arrived in Veun Kham, where a new ramp was hacked into the riverbank underneath some overhanging stilt houses.

As the operation to put the hovercraft back on the river was underway, the passengers were spirited away by the tour director to unlock another secret wonder of the Mekong. From 10.30-11.30, we watched the rare fresh water Irrawaddy dolphins.

After an hour of dolphin watching, under the protective eyes of the Cambodian border police, we returned to Veun Kham to find the hovercraft sliding back into the water.

Nov 13^th Wednesday. This morning we had breakfast at 5.30. At 6.00 we took the ferryboat across the river to Ban Hat and drove to Ban Veun Kham to reach our waiting hovercraft. After getting our passports stamped out of Laos, we crossed over to the Cambodian border post of Dong Crolor at 7.30. There, more than a handful of immigration officials headed by the chief of the Immigration office in Phnom Penh, boarded the boat to inspect our passports and let us pass quickly at the unofficial international border crossing point between Laos and Cambodia.

Because of the efficient work of the Cambodian immigration officials, we reached Stung Treng on the river mouth of the Sesan River into the Mekong at 9.00. A local French speaking guide of Diethelm Travel Cambodia and two pilots accompanied us. In addition, the head of the Phnom Penh immigration office returned with us on a journey which is 410 km. long and will last more than ten hours.

At 11.30 we passed the dangerous Sambor Rapids, where also some Irrawaddy dolphins abound. At 12.00, we landed at the port of Kratie.  After refueling the hovercraft, we got a new passenger, Mr. Sok Sokun from the Ministry of Tourism, who accompanied us to Phnom Penh.

At 16.00, we arrived in Kampong Cham. The town is an important communications hub with some interesting colonial buildings and a very big marketplace.

The last hour on the river was in the dark. We finally arrived in Phnom Penh at 19.15. We were all very tired but happy when we were transferred to the Royal Phnom Penh Hotel and had our dinner prepared in the Bassac Restaurant. By 22.00, most of the passengers fell asleep and only a few had the energy to go out to the riverside to savour the delights of the local nightlife.

Nov 14^th Thursday. At 5.30 there was the morning call. Today’s itinerary was most interesting. We had to follow the Tonle Sap River for at least 250 km. upwards to reach Angkor, the jewel in the crown of Cambodia’s historical achievements and the font of enormous spiritual energy.

We had breakfast at 6.00 and headed down the to the riverside. We departed at 6.30 to embark on a river journey from Phnom Penh to Siem Reap in the northwestern part of Cambodia. We welcomed the wife and son of Armin Schoch on board and also Charlotte McDonald-Gibson, a reporter from the local Phnom Penh Post.

The Tonle Sap Basin is notable for its great lake at its upper reaches, where the port of Siem Reap is located. The Tonle Sap River is a vital natural regulator of the region’s Mekong River and plays a crucial role in water regulation. An interesting phenomenon occurs during the rainy season from July to October in that the Mekong River carries so much floodwater that it feeds into the Tonle Sap River, causing it to reverse its course and flow upwards. As a result, the river becomes a very large fresh water lake that increases from 2,500 to more than 10,000 square km and doubles its depth.

At 14.15, after seven hours on the hovercraft, we reached the port of Siem Reap at the foot of Phnom Krom, where a whole delegation of the local Diethelm Office welcomed us.

At 17.00 we explored Angkor Wat, where we had a fine sunset to see the stone carvings with amazing battle scenes and 1850 “apsara” dancers. By any standards, this was the cultural highlight of our Expedition Mekong. Everyone was really tired after our Western dinner at the newly established Foreign Correspondence Club in Siem Reap, which we left at 21.00 to go back to the hotel.

Nov 15^th Friday. We spent most of the day sightseeing around Siem Reap and its environs.

At 15.00 we checked out from the Sofitel Royal Angkor Hotel and headed to the airport, where we took off with Siem Reap Airways at 17.00 to arrive in Phnom Penh 40 minutes later.

Three of our group departed: Humphrey Wou, Paul Davies and Peter Wennberg. Also, the skeleton crew of the hovercraft had gone back to Phnom Penh alone on the river with the Phnom Penh Post reporter. There was the daily rush hour and a downpour in Phnom Penh, so that we reached the Royal Phnom Penh Hotel at 19.00.                                                                  

Nov 16^th Saturday. Today’s cruise from Phnom Penh to Can Tho in the Mekong Delta will be some 240 km. We had our buffet breakfast at 7.00 and departed the Royal Phnom Penh Hotel at 7.30 to go back to the port. We left the port at 8.00

At Phnom Penh the Bassac River leaves the main arm of the Mekong River, which is called the Tien Giang by the Vietnamese. It is here that the fertile Mekong Delta begins, a triangular area that is by far the most densely populated part of the basin, supporting some 15 million people on about 50,000 square km. of recent alluvium.

At 11.00 we arrived at the river border of Khaorm Samnor Kaoh Roka. We had to wait 45 minutes to pass immigration, customs and health quarantine services to continue by boat to the Vietnamese immigration checkpoint of Song Tien. There, we met Nguyen Van Cu, our Diethelm guide from Hanoi, and a special pilot team to guide us to Can Tho.

At 12.45 we departed into the heart of the Mekong Delta. The present network of rivers and canals in the Mekong Delta totals more than 10,000 km. of waterways.

At 15.15 we reached Long Xuyen at the Hau Giang River. The town is an important industrial center and a very busy ferry point.

At 16.45 we reached the industrial port of Can Tho, after a cruise of seven hours. The provincial centre, containing a huge statue of Ho Chi Minh, is the de facto capital of the Mekong Delta and an important university town. After waiting a while for refueling the hovercraft and our transport to the Victoria Hotel, at 17.30, we decided to go by hovercraft to reach our hotel, where the general manager of the hotel, Ivan Casadevall, and the very friendly hotel staff awaited us. We checked in shortly after sunset and had a dinner reception at 19.30. San Miguel flowed freely but with the last emotional stretch of the journey before us, we made it to bed long before midnight.

Nov 17^th Sunday. As there was some uncertainty as to which way in the Mekong Delta the pilots would bring us to our final destination of Ho Chi Minh City, we had breakfast at 6.30 and left the pier of the hotel at 7.30. We followed the Mang Thit Canal in a northeast direction back to the Tien Giang and passed the morning market of Tra On in Vinh Long Province at 8.00.

At 9.15 we arrived in Mang Thit, from where we crossed over from Vinh Long Province to Ben Tre Province and reached the port of Cai Mon. At 9.45 we came to Cho Lach. Near this market town there was heavy traffic ahead on the river with convoys of boats laden with wood and sugar cane. We came back to the Tien Giang River at 10.15. The river here is wide and stormy like the sea. Back on the broad Tien Giang River we still needed one more hour to reach the river port of My Tho in Tien Giang Province, just 60 km. southwest of Ho Chi Minh City.

At 11.30 and 40 km. before reaching the South China Sea, we turned into the small Cho Gao Canal leading to Long An Province.

At 13.00 we reached the Can Duoc River which we had to follow to reach Rach Cat. At 14.00 we passed the industrial estate and ferry point of Nha Be. We had to change our pilot again to find the passage and to reach the confluence with the Saigon River, where ocean-going ships appeared. The Saigon River is actually not part of the Mekong River Basin, but belongs to the Dong Nai River Basin, having its sources in the Central Mountains of Vietnam. At 14.30, we could already recognize the silhouette Ho Chi Minh City and finally arrived in Saigon Port at 15.00, after a steady cruise of seven and half hours.

At the pier, some female staff members from Diethelm Travel Vietnam were waiting with a big welcome banner. At 16.00 we were transferred by bus to the Sofitel Plaza Saigon Hotel, where Jacques Serpollier, general manager, and Bertrand Coutois, executive assistant manager in charge of rooms, gave us a speedy check in.

At 19.00 we had our farewell dinner and continued downtown into the night. Some made it home early in the morning.

Nov 18^th Monday. After 15 days covering almost 3,000 km. through six countries, the official end of Expedition Mekong has arrived. Everyone used the free morning to feast on the international buffet breakfast of Café Rivoli.

All we had to do now was to return the hovercraft to Yunnan. All the responsibilities were handed over to the tour director. The skeleton crew for the hovercraft went to the Palace Hotel to await the return departure day on Nov 21^st.

The final departure of the members of the expedition arrived in the evening. At 19.00 we said farewell before the departure by plane back to Bangkok and beyond. The tour director stayed behind and will bring back the hovercraft to China after a rest of some days.

After a cerebrally stimulating question and answer session, the meeting adjourned to the Alliance Cafeteria where members of the audience plied Reinhard with drinks and snacks as they engaged him in more informal discussions.