费德里科·路易吉Luigi Federico Menabrea

费德里科·路易吉在都灵大学学习工程学和数学，之后成为军队中的工程师。他的职业生涯非常卓越，对科学作出了非常重大的贡献，同时也在军事和政治生活中达到了最高层次。为了理解他生平的背景，我们需要简要看一下意大利的政治局势。

大多数意大利人的目标是建立一个统一的意大利国家，但对于如何实现这一目标存在不同想法。一些人赞成由国王统治的统一意大利，另一些人则寻求共和国。奥地利控制着该国一些渴望成为统一意大利一部分的地区，而法国虽然扮演着重要角色，但其立场并不那么明确。当然，还有由宗教领袖即教皇统治的教皇国的“问题”。拿破仑对欧洲大部分地区控制的终结，见证了维也纳会议（1814—15）在意大利建立了一种政治秩序，这种秩序基本上贯穿了路易吉生命的最初60年。它创建了如尼斯、萨伏依和皮埃蒙特等由萨伏依国王维克托·伊曼纽尔一世统治的国家。奥地利的弗朗茨一世也成为伦巴底-威尼西亚国王，驻扎在费拉拉的奥地利军队随时准备在必要时干预教皇国。奥地利还有权干预两西西里王国，威尼西亚和伦巴底则成为奥地利帝国的一部分。1831年，Charles Albert成为萨伏依国王。他强烈反奥，想要把奥地利人赶出意大利半岛。另一个希望赶走奥地利人的是加富尔，他与路易吉一样，当时正从事军事生涯。当局对他的动机产生怀疑，将他派往阿尔卑斯山的巴尔多要塞，使他远离要职。加富尔辞职，1831年由路易吉接替。

路易吉很快从巴尔多要塞调离，成为撒丁王国军事学院和都灵大学的力学与建筑学教授。1840年8月，查尔斯·巴贝奇在都灵科学院就他的分析机作了一系列讲座。这次活动是意大利科学家第二次大会，邀请是以国王Charles Albert的名义发出的。他应普兰纳邀请作讲座，并期望普兰纳将讲座整理出版。然而，这项任务被分配给路易吉，这一定让查尔斯·巴贝奇感到失望，因为普兰纳是一位杰出科学家，而他几乎肯定从未听说过路易吉。然而大会非常成功，除了查尔斯·巴贝奇的讲座外，还有关于分析机的讨论会，参与者包括查尔斯·巴贝奇、路易吉和意大利天文学家奥塔维亚诺·莫索蒂。路易吉将讲座整理成文，并根据讨论中的想法作了修改，写成论文Notions sur la Machine Analytique de M Charles BabbageⓉ（查尔斯·巴贝奇分析机基础），该文于1842年10月以法文发表在Bibliothèque Universelle de Genève上。

这就是拜伦勋爵的女儿阿达·洛夫莱斯发表译文的那篇论文，译文附有大量注释和对分析机工作原理的进一步说明。

这篇文章发表后不久，路易吉开始了他的政治生涯。到1848年，他成为国王Charles Albert信任的助手，国王派他执行多项重要外交使命。1848年是欧洲许多国家发生革命的一年，人民抗议他们的统治者。弗朗西斯·斐迪南五世一度被逐出摩德纳，但被奥地利军队恢复。路易吉被派往摩德纳执行外交使命，以确保其仍属于撒丁王国。1859年8月20日，摩德纳宣布自己成为意大利王国的一部分。他还被派往帕尔马执行类似使命。此后，路易吉进入皮埃蒙特议会，先隶属于战争部，后隶属于外交部。

在这段从政时期，他继续做出色的科学工作，首次精确表述了基于虚功原理的结构分析方法，该原理最早于1857年提出。他还在Nouveau principe sur la distribution des tensions dans les systèmes élastiqueⓉ（关于弹性系统中张力分布的新原理）中研究了弹性与最小功原理，该文于Comptes rendus1858年发表。路易吉原理指出，对于与连续介质静力学方程及边界条件相容的任何可能的应力变化系统，处于完全弹性平衡的物体的弹性能取最小值。1868年，他在Études de Statique Physique - Principe général pour déterminer les pressions et les tensions dans un système élastiqueⓉ（静力学物理研究——确定弹性系统中压力和张力的一般原理）中发表了对该原理的改进证明。1870年，他与约瑟·伯特兰联合发表了该原理的第一个完全正确的证明。Castigliano曾与路易吉就该原理发生争论，他因分析力学中的功和能量概念而更为人所知。路易吉后来发表了两篇进一步的文章，回应Castigliano的批评。

路易吉的这项科学工作发生在他仍更深入参与政治和军事工作的时期。他一直致力于为意大利统一问题寻求妥协方案，直到1859年都相信梵蒂冈与国家之间的妥协是可能的。然而1859年爆发了一场战争，由加富尔和法国拿破仑三世组织，在意大利北部对抗奥地利人。路易吉重新担任少将和工程师总指挥的领导军事角色，参与伦巴第军事战役。位于加尔达湖东南端的佩斯基耶拉是奥地利人的四个设防城镇之一，路易吉组织了针对它的围攻工事。他还运用工程技能淹没奥地利军队正在推进的平原。当曼弗雷多·凡蒂对奥地利取得辉煌胜利时，路易吉正在帕莱斯特罗。他还参与了1859年6月24日的索尔费里诺战役——在那里对奥地利人的战斗是第二次意大利独立战争的最后一场交战。意大利北部此时已统一为意大利王国。

1861年，路易吉被任命为中将，并参与指挥对加埃塔的围攻。加埃塔于1861年向意大利王国投降，标志着波旁两西西里王国的终结。路易吉此时再次转向政治，于1861年6月至1862年5月在贝蒂诺·里卡索利的内阁中担任海军大臣。随后，他于1862年12月至1864年9月在法里尼·明盖蒂的内阁中担任公共工程大臣。1866年又爆发了与奥地利的战争，意大利王国从奥地利人手中夺取了威尼托。路易吉被意大利王国授予全权，在战争结束时的布拉格条约中与奥地利谈判威尼托的移交事宜。事实上，他不得不应对奥地利人的一个诡计，他们于10月12日将威尼托交给法国，试图使该领土不落入意大利人之手。然而一周后，拿破仑三世将威尼托割让给意大利。

1867年10月27日，路易吉接替乌尔巴诺·拉塔齐任意大利首相。他任职至1869年12月14日，因新议会选出而他不占多数，遂辞职；由乔瓦尼·兰扎接替。在此期间（其间有三届内阁），路易吉不仅担任首相，还兼任外交大臣。这并非一个容易担任首相的时期。在他任职期间，加里波第率军进军罗马，试图夺取教皇国。法国支持教皇，法国军队在门塔纳击败了加里波第的志愿军。尽管路易吉曾秘密支持加里波第，政府也为这次失败的冒险提供了资金，但他不得不在1868年10月27日发布公告，对加里波第提起法律诉讼。这当然是在玩弄政治，因为路易吉坚信教皇应领导罗马天主教会，而不是成为一个国家的元首。他还强烈支持罗马成为意大利王国的一部分。这在他任职期间未能实现，但他作为首相的一项成功是取消了面粉等物品上不受欢迎的税收。

乔瓦尼·兰扎接任首相后，意识到路易吉可能仍通过与国王维托里奥·埃马努埃莱二世的密切接触而保持实质权力。因此，兰扎认为最好将路易吉调离事件中心，他通过任命其为驻伦敦大使来做到这一点。1875年，他被封为瓦尔多拉侯爵。1882年，他被任命为驻巴黎大使，接替恰尔迪尼将军，并继续担任此职，直到1892年退出公共生活。

Luigi Menabrea studied engineering and mathematics at the University of Turin, then became an engineer in the army. His career was a remarkable one in which he made very significant contributions to science, yet also reached the highest levels in military and political life. In order to understand the background to his life we need to look briefly at the political situation in Italy.

The aims of most Italians was a unified Italian state, but there were different ideas as to how to approach this. Some favoured a unified Italy ruled by a king, others looked for a republic. Austria controlled parts of the country which aspired to become part of the unified Italy while France played an important role, yet their position was not as well defined. Then of course there was the 'problem' of the Papal States which were ruled by a religious leader, namely the Pope. The end of Napoleon's control of much of Europe saw the Congress of Vienna (1814-15) establish a political order in Italy that lasted essentially through the first 60 years of Menabrea's life. It created states such as that of Nice, Savoy, and Piedmont ruled by King Victor Emmanuel I of Savoy. Francis I of Austria also became king of Lombardy-Venetia and Austrian troops stationed at Ferrara were there to intervene in the Papal States if necessary. Austria also had the right to intervene in the Kingdom of the Two Sicilies, and Venetia and Lombardy became part of the Austrian empire. In 1831 Charles Albert became king of Savoy. He was strongly anti-Austrian and wanted to drive the Austrians from the Italian peninsula. Another who wished to drive out the Austrians was Cavour who, like Menabrea, was at this time following a military career. The authorities became suspicious of his motives and he was sent to the Alpine fortress of Bardo where he was out of the way. Cavour resigned and he was replaced in 1831 by Menabrea.

Menabrea soon moved from the fortress of Bardo to become professor of mechanics and construction at both the Military Academy of the Kingdom of Sardinia and at the University of Turin. In August 1840 Charles Babbage gave a series of lectures on his Analytical Engine at the Academy of Sciences in Turin. The occasion was the second congress of Italian scientists, and the invitations had come in the name of King Charles Albert. He had been invited to give the lectures by Giovanni Plana and expected that Plana would write up the lectures for publication. However, Menabrea was assigned to the task, something which must have disappointed Babbage since Plana was a distinguished scientist whereas he had almost certainly never heard of Menabrea. However the congress was a great success and in addition to Babbage's lectures there were discussion sessions on the Analytical Engine which involved Babbage, Menabrea, and the Italian astronomer Ottaviano Mossotti. Menabrea wrote up the lectures, modified with ideas from the discussions, in the paper Notions sur la Machine Analytique de M Charles Babbage Ⓣ which was published in French in Bibliothèque Universelle de Genève in October 1842.

This was the paper which Lord Byron's daughter Ada Lovelace published a translation of with extensive notes and further illustrations of the working of the analytic engine.

Not long after the publication of this article Menabrea began his political career. By 1848 he became a trusted helper of King Charles Albert who sent him on a number of important diplomatic missions. Now 1848 was the year in which revolutions took place in many countries in Europe, with people protesting against their rulers. Francis Ferdinand V was temporarily expelled from Modena but was restored by Austrian troops. Menabrea was sent on a diplomatic mission to Modena to make sure that it remained part of the Kingdom of Sardinia. On 20 August 1859 Modena declared itself part of the Kingdom of Italy. He was also sent on a similar mission to Parma. After this Menabrea entered the Parliament of Piedmont and was attached to the Ministry of War, then later to the Ministry of Foreign Affairs.

During this period of politics he continued to do excellent scientific work, giving the first precise formulation of methods of structual analysis based on the principle of virtual work first presented in 1857. He also studied elasticity and the principle of least work in Nouveau principe sur la distribution des tensions dans les systèmes élastique Ⓣ published in Comptes rendus in 1858. The principle of Menabrea states that the elastic energy of a body in perfect elastic equilibrium is a minimum with respect to any possible system of stress-variation compatible with the equations of the statics of continua in addition to the boundary conditions. In 1868 he published an improved demonastration of his principle in Études de Statique Physique - Principe général pour déterminer les pressions et les tensions dans un système élastique Ⓣ. He published, jointly with J L F Bertrand, the first completely correct proof of this principle in 1870. Castigliano, with whom Menabrea was in dispute regarding this principle, became better known for the concepts of work and energy in analytical mechanics. Menabrea later published two further papers answering the criticisms of Castigliano.

This scientific work by Menabrea took place at a time when he was still more heavily involved in politics and military work. He had always worked for a compromise solution to the Italian unification question and up to 1859 believed that a compromise between the Vatican and the state was possible. However in 1859 there was a war which Cavour and Napoleon III of France organised against the Austrians in north Italy. Menabrea resumed a leading military role as major-general and commander-in-chief of the engineers in the Lombard military campaigns. Peschiera, at the southeast end of Lake Garda, was one of the four fortified towns of the Austrians and Menabrea organised the siege works against it. He also used his engineering skills to flood the plains through which the Austrian army was advancing. Menabrea was present at Palestro when Manfredo Fanti scored a brilliant victory against Austria. He was also involved at Solferino on 24 June 1859 - the battle against the Austrians there being the last engagement of the second War of Italian Independence. The northern part of Italy had now been unified as the Kingdom of Italy.

In 1861 Menabrea was appointed lieutenant-general and was involved in conducting the seige of Gaeta. Gaeta's capitulation to the Kingdom of Italy in 1861 marked the end of the Bourbon Kingdom of the Two Sicilies. Menabrea now turned again to politics and was appointed Naval Minister in the cabinet of Bettino Ricasoli from June 1861 to May 1862. He then served in the cabinet of Farini Minghetti as Minister of Public Works from December 1862 to September 1864. The year 1866 saw another war with Austria in which the Kingdom of Italy captured Venetia from the Austrians. Menabrea was given full authority by the Kingdom of Italy to negotiate with Austria the hand over of Venetia at the Treaty of Prague at the end of the war. In fact he had to contend with a trick from the Austrians who gave Venetia to the French on 12 October in an attempt to keep the territory out of Italian hands. However one week later Napoleon III ceded Venetia to Italy.

On 27 October 1867 Menabrea succeeded Urbano Rattazzi as Prime Minister of Italy. He served until 14 December 1869 when he resigned since a new chamber had been elected in which he did not hold a majority; he was replaced by Giovanni Lanza. Not only did Menabrea hold the position of Prime Minister during this period (during which there were three cabinets), but he also held the position of Foreign Minister. It was not an easy period in which to be Prime Minister. During his office Garibaldi led an army on Rome in an attempt to capture the Papal States. France supported the Pope and French troops defeated Garibaldi's volunteers at Mentana. Although Menabrea had secretly supported Garibaldi, and the government had put up money for the failed venture, he had to issue a proclamation on 27 October 1868 starting legal proceedings against Garibaldi. Certainly this was playing politics for Menabrea strongly believed that the Pope should lead the Roman Catholic Church, not be head of a country. He also strongly supported Rome becoming part of the Kingdom of Italy. This was not achieved during his period of office but one of his successes as Prime Minister was to scrap unpopular taxes on items such as flour.

After Giovanni Lanza took over as Prime Minister he was aware that Menabrea might still keep substantial power through his close contacts with King Victor Emmanuel II. Lanza, therefore, thought it better to remove Menabrea from the centre of events and he did this by appointing him ambassador to London. He was made Marquis of Valdora in 1875. In 1882 he was appointed as ambassador in Paris, replacing General Cialdini, and he continued in this role until he retired from public life in 1892.