In Hornsund Fiord, West Spitsbergen, the cobblees with varnish coat on their surface were found. They occur on low Holocene terraces on older and lower moraine ridges of Hans Glacier. There are two types of chemical coats: 1. corresponding to the mineral and chemical substance of the rock they occur on, and 2. independent of the rock, sedimented under influence of external activities. First type of coats is created by oxidative processes. The second type, like manganese-iron coats of intensive dark colours, does not differ from the phenomenon defined as "desert varnish". They were developed in Holocene in present conditions of polar climate. The authors lean toward biological origin of the coats.
Two violins were investigated. The only intentionally introduced difference between them was the type of varnish. One of the instruments was covered with a spirit varnish, the other was oil varnished. Experimental modal analysis was done for unvarnished/varnished violins and a questionnaire inquiry on the instrument’s sound quality was performed. The aim of both examinations was to find differences and similarities between the two instruments in the objective (modal parameters) and subjective domain (subjective evaluation of sound quality). In the modal analysis, three strongly radiating signature modes were taken into account. Varnishing did not change the sequence of mode shapes. Modal frequencies A0 and B(1+) were not changed by oil varnishing compared to the unvarnished condition. For the oil varnished instrument, the frequency of mode B(1+) was lower than that of the same mode of the spirit varnished instrument. Our two violins were not excellent instruments, but before varnishing they were practically identical. However, after varnishing it appeared that the oil-varnished violin was better than the spirit-varnished instrument. Therefore, it can be assumed with a fairly high probability that also in general, the oil-varnished violins sound somewhat better than initially identical spirit-varnished ones.