Ten years after he married Martine de Bertereau, who thenceforth became his companion in all his travels, his fellow-labourer in the same field of science, and who even surpassed him in ability and skill in detecting the indications of ore. The couple examined together the German, Italian, and Swedish mines. She then crossed the Atlantic to investigate those of the New World. She next applied herself to the study of chemistry, geometry, hydraulics, and mechanics, and became accomplished in each of these sciences. She was able to speak fluently Italian, German, English, Spanish, French, and was a Latin and Hebrew scholar. In 1626, Cinq-Mars, then superintendent of the mines, gave the Baron a commission to traverse several of the provinces, and open mines wherever he found indications of ore. Whilst thus engaged, the Baron published a volume on The True Philosophy concerning the First Matter of Minerals, a work of no great value, as it is overloaded with the absurd theories of the metamorphosis of metals then in vogue.
The course of his investigations led him and his wife to Morlaix, in Brittany, and there, in 1627, an event took place which gave them considerable annoyance, as well as proving a severe pecuniary loss. The Baron was engaged in examining a mine in the forest of Buisson-Rochemarée, and his wife was at Rennes seeing to the registration of their commission. Taking advantage of the absence of both at the same time, a provincial provost, Touche-Grippé by name, of the race of Dogberry, made an entry into their house, under the plea of search after magical apparatus, for, as the provost said, “How can mortal man discover what is underground without diabolical aid?” On this pretext, then, the house was ransacked, and Dogberry laid violent hands on every article which aroused his curiosity or attracted his cupidity. The boxes were broken open, the cupboards burst into, the drawers searched, and gold, silver, jewels, mineralogical specimens, scientific instruments, legal documents, notes of observations made in the course of travel, every fragment of manuscript, private letters, and maps, were carried off by Touche-Grippé and appropriated to his own use.
On the return of the Baron and Baroness to Morlaix they found that, in addition to this robbery in the name of justice, a charge was laid against them of magic. They were constrained to appear before Touche-Grippé and a fellow-magistrate of like nature, and free themselves of the charge. They were allowed to depart exculpated, but without their property, which the magistrate refused to surrender. The Baron appealed to the Parliament of Brittany, but without obtaining any redress; he then applied to that of Paris, but Touche-Grippé had friends at court, and the appeal of the Baron was rejected. Twelve years after, in 1640, we find the Baroness still asking for redress, and still in vain.
The failure of the couple in obtaining any attention so irritated them that they left France and returned to Germany, which had always recognised their services, and treated them with the respect due to their abilities and attainments. Ferdinand II. at once placed the Baron de Beausoleil in charge of the Hungarian mines.
But, unfortunately, the nobleman and his wife were not content to remain in Germany, and after a few years resolved on trying their fortune once more in France. This time they determined on carrying on their operations upon a more extensive scale, and in 1632 they entered the kingdom of Louis XIII., accompanied by fifty German and ten Hungarian miners, together with private servants. The king at once renewed the commission given by Cinq-Mars in 1626, and the Baron commenced a series of explorations in Brittany and in the south of France. The Parliaments of Dijon and Pau having objected to the commission, the king issued an order to them to recognise the Baron and his wife, and to aid them in their search after minerals by affording them every facility which lay in their power. Notwithstanding this apparent royal support, the two mineralogists obtained no pecuniary assistance from Government, but were expected to carry on all their operations at their private expense. The maintenance of sixty miners, the prosecution of extensive works, and the travelling from province to province, could not fail to reduce the means of the couple very considerably. A little glory might accrue to them, but they were sure of becoming the objects of jealousy; they obtained praise from the king, but no money; and after having expended 30,000 livres—in fact, their whole fortune—they were as far from obtaining any pecuniary acknowledgment of their services as they were when first entering France. In 1632 the Baroness addressed a memoir to the king on the mineral treasures of the country; it was entitled, “Veritable Declarations made to the King and his Council of the rich and inestimable Treasures lately discovered in the Kingdom”; but as this met with no response, she reprinted it under the title “Veritable Declarations of the Discovery of Mines and Minerals in France, by means of which his Majesty and his subjects will be enabled to do without Foreign Mineral Trade; also concerning the Properties of Certain Sources and Mineral Waters lately discovered at Château-Thierry by Madame Martine de Bertereau, Baroness de Beausoleil.” In this interesting memoir one hundred and fifty mines are indicated as having been discovered by the Baron and his wife. The Government, satisfied of the value of the services of the two foreigners, but unwilling, for all that, to pay them, now, as acknowledgment, conferred on them a new brevet, giving them extended powers, and elevating the Baron to the grade of Inspector-General of all the mines in France. If glory alone could suffice as a reward to merit, the Baron du Châtelet and Madame de Bertereau must have felt content with the dignity now conferred upon them. But a glory which cost them their whole fortune, and which in no way repaid their labours, must have seemed to them a bitter deception.
Little by little the worthy couple had to reduce their retinue and to curtail their expenses, and after ten years of unrequited exertion in behalf of the crown, their train was scanty enough. However, their hopes were not yet exhausted, promises had been made to them of the most brilliant description, and they relied upon the honour of the French crown to redeem them.
In 1640 the Baroness appealed to Cardinal Richelieu in a pamphlet entitled “La Restitution de Pluton à l’Eminentissime Cardinal Duc de Richelieu,” a second title-page adds, “with a refutation of those who believe that mines and subterranean matters are only discovered by magic and by the aid of the devil.”
Whether the Cardinal read the memoir or not, we cannot say, but undoubtedly he perused the dedicatory epistle, or, at all events, the sonnet it contains, which sums up its flatteries and hyperbolic compliments.
Esprit prodigieux, chef-d’œuvre de nature,
Elixir épuré de tous les grands esprits,
Puisque vous conduisez notre bonne aventure
Arrêtez un peu l’œil sur ces divins écrits.
Ces écrits sont dressés pour une architecture,
Dont la sainte beauté vous rendra tout épris;
Le soleil et les cieux conduisent la structure,
Et vous, vous conduisez cet ouvrage entrepris.
La France et les Français vous demandent les mines;
L’or, l’argent, et l’azur, l’aimant, les calamines,
Sont des trésors cachés par l’esprit de Dieu.
Si vous autorisez ce que l’on vous propose,
Vous verrez, Monseigneur, que, sans métamorphose,
La France deviendra bientôt un Riche-Lieu.
The Restitution of Pluto is a book most interesting, not only on account of the erudition and rare acquaintance with natural philosophy which it displays, but also from the stately and vigorous writing of the authoress. It contains passages glowing with energy, and is composed in a style of dignified and manly eloquence. Maybe the publication of this work opened the eyes of the Cardinal to the fact that the State certainly was indebted to this illustrious couple for services gratuitously rendered during upwards of ten years. The most convenient method of paying them was that of silencing the voices which cried for acknowledgment, and thus stifling the claims on the royal exchequer. Slanderous reports were circulated relative to the Beausoleils, and they were accused of various crimes. The suspicion of magic, which had attached to them from the time of the inquisition of the provost of Morlaix, was revived, and the prejudices of the age tended to give it force to overthrow the noble pair. Old superstitions concerning gnomes of the mines and subterranean demons were not yet extinct. The Baroness herself believed in them, and in one of her works speaks of her having encountered some of them. In the mines of Neusol and Chemnitz in Hungary, she says, “I saw little dwarfs about three or four palms high, old, and dressed like miners, that is, clothed in an old suit, and with a leather apron, a white tunic and cap, a lamp and staff in hand—terrible spectres to those who are unaccustomed to mines.” Several times already, as appears from her writings, she and her husband had been exposed to the violence of the rude and ignorant rustics, who thought their scientific instruments means for conjuring up the devil, and the authorities were, as we have seen at Morlaix, quite prepared to second the popular superstition when profit could be obtained thereby. The divining rod, then much in vogue in Germany, was used by the Baron and his wife, who had strong belief in its magnetic properties, and the employment of it may have given some colour to the charges now raised against them on all sides of being necromancers in league with evil spirits.