INDUSTRIES 



The procedure in quarrying granite is briefly 

 as follows. A suitable position for opening a 

 quarry having been determined on, the subsoil 

 and loose and poor rock are removed. When 

 this is finished, an examination of the joints is 

 made, and the discovery of a good bed or hori- 

 zontal joint determines the proper position for 

 boring a hole to receive the explosive. The 

 object is to dislodge a mass from its natural 

 position with as little alteration as possible in its 

 form, and it is therefore very important that all 

 obstacles which might impede its free movement 

 should be removed. Any neglect in this re- 

 spect may result in the rock being shattered. 

 It will therefore be understood that a great 

 amount of judgment and experience is required 

 to quarry successfully, and a hasty or ill- 

 considered operation will most probably result 

 in not only spoiling the rock to be moved, but 

 also cracks may be developed in the rocks 

 remaining in situ, and these may lead to trouble 

 later on. 



When the rock has been dislodged by the 

 successful firing of the hole, the quarrymen 

 split it up into the smaller blocks to make 

 the various-sized stones required. The splitting 

 is accomplished by steel wedges inserted into 

 numerous small holes drilled by hand across the 

 various faces of the large rock, in such positions 

 and in such lines as are determined by the 

 experience of the quarryman. 



The dressing of the blocks for engineering 



works, as before mentioned, is done in the 

 quarries ; but for building purposes, and for work 

 which requires great care and skill, the dressing 

 is usually done in the dressing yards adjacent to 

 the shipping quays. 



Mention has been made of blondins as applied 

 to the quarries. These lifting and transporting 

 machines take their name from the famous 

 acrobat and rope-walker who successfully ex- 

 hibited his wonderful powers at Niagara Falls. 

 The machine consists of a wire rope stretched 

 across the quarry on which a carriage runs. 

 This carriage can be made to travel to and fro 

 on the rope by means of smaller ropes, which 

 are controlled from a steam winch, conveniently 

 placed so that the driver has an uninterrupted 

 view of the quarry. The carriage has a lifting 

 rope in connexion with it which is also con- 

 trolled from the steam winch. Such machines 

 command a very wide range, and as they are 

 arranged to work at a high rate of speed they 

 are particularly adapted to quarry work. 



It is well known that the tin industry of 

 Cornwall has materially suffered from foreign 

 competition. It appears likely that history will 

 repeat itself, and the granite industry of the 

 county will suffer in the same way. Of late 

 years the vast resources of Scandinavia have 

 been requisitioned. Abundance of granite is 

 found there, in such positions and under such 

 conditions that it is already proving a very 

 formidable rival to the Cornish stone. 



SLATE QUARRYING 



The slate-quarrying industry of Cornwall has 

 been of importance for at least three centuries, 

 and especially during the last hundred years. 

 Many efforts have been made to trace its history, 

 but no authentic records of its commencement 

 have been discovered. The earliest record found 

 is that of Norden, who, writing in the year 1584, 

 describes Menheniot slate as the best in Corn- 

 wall. Carew, writing in 1602 in reference to 

 Cornish roofing slate, is more explicit : ' In 

 substance thin, in colour fair, in weight light, in 

 lasting strong ; and generally carrieth so good 

 regard, as (besides the supply for home provision) 

 great store is yearly conveyed by shipping both 

 to other parts of the realm and also beyond the 

 seas into Brittany and the Netherlands.' 1 

 Borlase again, writing in 1758 of Delabole slate, 

 says that for lightness and endurance of weather 

 it is generally preferred to any slate in Great 

 Britain, and is perhaps the finest in the world. 

 Sir H. T. De la Beche, F.R.S., says Delabole 

 quarries have long been celebrated for producing 

 a beautiful and durable material combining con- 



1 Carew's Survey of Cornwall, p. 20 (ed. 1811). 



siderable lightness with strength, and not liable 

 to be damaged by frost. Delabole slate is 

 described by Bishop Watson in his Chemistry as 

 the very best in England. In 1865 Frederick 

 Penny, Professor of Chemistry at the University 

 of Glasgow, writes : ' I have made a scrupulous 

 comparison of the Old Delabole slate with the 

 Welsh, Highland, and Cumberland slates ; the 

 results showing that the Old Delabole slate is of 

 very superior quality. It is light in colour, 

 thin and firm in lamination, close and compact 

 in texture, extremely hard, and not easily worn 

 by attrition. In strength and endurance of 

 weather and friction it excels these well-known 

 slates.' At the time of Borlase and De la 

 Beche there were within six miles of Delabole 

 many small quarries, but they were chiefly 

 worked by small bodies of men. Most of them 

 were worked for only a few years ; either the 

 beds of slate rock were small and worthless, or 

 the rock was so unproductive that it could only 

 be worked at a loss. For some years past there 

 have been only two quarries at work besides 

 Delabole namely, Lanterden and Lambshouse. 

 Both are in the parish of Tintagel. 



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