REPORT OF THE STATE GEOLOGIST. XXXIX 



sufficiently for it to serve as a bond or cement under the semi-fusion 

 caused by the heavy pressure which is applied to make it cohere. Such 

 coals as do not form their own cement in this way are made to cohere 

 by the addition of various cementing materials, such as bitumen, coal 

 tar, pitch, starch, potatoes, clay, etc. 



Lignites prepared in this way are fully equal to ordinary bituminous 

 coal as fuel for all purposes, and possess, in addition, several important 

 advantages. They are more compact, and are in the regular form of 

 blocks which can be stored in four-fifths the amount of space occupied 

 by the same weight of coal. They are much cleaner to handle, and 

 the waste in handling, which in the case of bituminous coal is often 

 as much as twenty per cent, is very little. 



Owing to its physical structure it burns with great regularity and 

 without clinkers, making it a very desirable steam fuel. For these 

 reasons it is often preferred to bituminous coal. 



Coke of excellent quality is made from lignites in ovens properly 

 constructed for the purpose. These ovens are of various designs suited 

 to different characters of lignite, but all accomplish similar results, and 

 the coke thus produced is used for all purposes for which other cokes 

 are adapted. 



Illuminating gas of very superior quality is manufactured from lig- 

 nites, and is in use in many German manufactories. 



Lignite also forms the base of many other important industries. Up 

 to the time of the discovery of the oil fields of America and the great 

 deposits of mineral wax, or ozocerite, the lignite was the principal 

 source of supply of paraffine and illuminating oils, and even now, al- 

 though comparatively few factories are run solely for their production, 

 as was formerly so largely the case, the amount manufactured as by- 

 products is very large. 



These substances are the results of distilling the lignites in the same 

 manner in which gas is produced from bituminous coal, and the product 

 consists of gas, water, tar, ammonia, coke, and ash. The tar contains 

 paraffine and mineral oils, as well as being the basis for the analine dyes 

 for the production of which great quantities of lignite are used. 



Powdered coke from lignites is used i,n the manufacture of. gunpow- 

 der, of blacking, and for filters, and is substituted in many places for 

 the more costly boneblack. 



Finally lignite is used very successfully in the place of boneblack in 



