The deliveries of optical devices

 

 

Rangefinders. At the end of the 19th century the Bulgarian artillery was provided with special optical devices. In 1892 the Russian Army tested in the Officers Rifle School at Oranienbaum a great number of rangefinder in order to choose the best device to equip its infantry units. On 5 August 1892 the Commission decided to adopt the prismatic pocket rangefinder invented by the French captain Souchier in 1888 (brevet 186052 du 20 octobre 1888), instructor at the École normale de tir at Châlons. That device was judged strong, light, extremely reliable and portable, accurate and easy to use, and above all very cheap. It was assigned to every infantry company, cavalry squadron and Cossak sotnia. On 1 May 1894 it was adopted also by the French infantry battalions.

It could be employed only for infantry, since its accuracy decreased for ranges up to 1000 m. The Russian captain Eroguin, however, invented a simple device to adapt the rangefinder to the Army field glass. In that way, the rangefinder could easily measure ranges from 5 km to 8 km, being utilizable also by the artillery.

The Bulgarian Army followed once more the Russian example and adopted the jumelle-télémètre Souchier (далекомер Суше) for its artillery, while no rangefinder was introduced for the infantry units. At the end of the century every battery received a rangefinder and the rules issued in 1902 stressed that firing at medium and long ranges, the distance should always determined by rangefinder.

 

At the end of the 19th Century, the fortress artillery was equipped with the Stroobants prismatic rangefinder (далекомер на Стробанса), adopted also by the Belgian infantry in 1894. It was lighter and smaller than the Souchier rangefinder, easy to use and very cheap.

 

In February 1906 cpt. Nikolov of the 34th Troyansky Infantry Regiment invented a new kind of rangefinder and proposed its adoption by the Army. The War Minister Mihail Savov set up a Commission presided by major general Georgi Vazov in order to test it. According with the official report, the rangefinder proved to be light and easy to use. Without a long practice, it could be handled by a man standing, kneeling or laying. As for its accuracy, on a distance of 500 m the error recorded was less than 3 m, up to 1108 m it rose to more than 4 m, and up to 2896 m attained 16 m, while in wide measurements at 2896 m with a width of 16 m, the error was 70 cm, and at 1250 m with a width 145 m it rose to 1 m.

After having examined the device and the practical results of its use, the Commission, taking into account the increased battle dynamics as well as the shortage of other reconnaissance tools, concluded that the Nikolov rangefinder was quite effective for both infantry and artillery. Nevertheless it seems that it was never adopted by the Bulgarian Army.

 

In 1909 some infantry and artillery units begun to test the most modern kinds of coincidence rangefinders : “Goerz”, “Zeiss”, “Hahn” and “Barr & Stroud”. The following year the Artillery Committee with Report Nr. 3/25-26 November 1910 concluded that all of them were solid, watertight and easy to use, the range being estimated from a single place in a minute. Among the artillery rangefinders the “Goerz” model was the most reliable, the error in setting being only 2-5% of the estimated range, while among the infantry ones both “Goerz” and “Barr & Stroud” were regarded as very effective. Nevertheless the Committee suggested the adoption of the “Goerz” model, since it had proved to be also the most solid. The infantry model could be carried by a soldier in a knapsack, the artillery one by horse in a bag.

Therefore the Bulgarian Army purchased from the German firm “Optische Anstalt C. P. Goerz A.G. Berlin – Friedenau” 36 rangefinders 65 cm base for the MG companies and 42 rangefinders 1 m base for the artillery. Every field and mountain artillery division received one of them, while the fortress battalion received two of them each. Bulgaria was the first country to adopt the Goerz rangefinder. In order to improve fire control, every battery of howitzers, field and mountain guns were also equipped with the “Goerz” panoramic sight.

 

Binoculars. At the beginning of the 20th Century the Bulgarian artillery was equipped with Galilean binoculars, mainly from the French firm “Huet” (“Societé Anonime des Anciens Établissements Huet et Cie. Paris”), that was also the supplier of the French Army, while a lot of officers were equipped with “Goerz” field glasses, with a magnification power of 8 times. With the introduction of the quick-firing artillery, more modern devices should be adopted. In 1911 the Artillery Committee tested some prismatic field glasses of the firms “Goerz”, “Zeiss” and “Huet”. All the models were achromatic and had parallel axis, but the two German models proved to be better both for optical features of the lens, the quality of the image (cleanness, definition and precision) and the solidity, being shockproof and watertight. Therefore with Report Nr. 2/30 April 1911 the Committee recommended for the officers the adoption of the binoculars of the firm “Zeiss” (“Carl Zeiss Optische Wekstätten Jena”), with a magnification power of 6 times, a highness of 25, and a field of vision of 150 millièmes.

 

Battery telescopes. On delivery the new quick-firing guns, were equipped with the battery telescope supplied by the firm. They had a magnification power of 17 times, but were not equipped with dual sight, and could be employed to conduct indirect fire. In order to find a more effective device, 1910 the Artillery Committee tested some battery telescopes of different firms. With the Report Nr. 2/30 September 1910, the Committee suggested to adopt the panorama battery telescope “Goerz”, with a magnification power of 8 times, since it was equipped with a goniometer very similar to the Schneider model in use into the Bulgarian artillery. It was capable of measuring both vertical graduations and horizontal angles, corresponded with to that of the sight. By its aid, the battery commander could determine the deflection allowances and measure the angles of site, required to fire from covered positions. It could also be used to observe the fire, and if necessary as a rangefinder. It could be carried by horses in two bags, one for the tripod and the goniometer, the other for the telescope. The “Goerz” battery telescope was assigned to the mountain and howitzers quick-firing batteries.