"Jolly balance" meaning in English

{
  "etymology_text": "Invented by the German physicist Philipp von Jolly in 1864.",
  "forms": [
    {
      "form": "Jolly balances",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {},
      "expansion": "Jolly balance (plural Jolly balances)",
      "name": "en-noun"
    }
  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "noun",
  "senses": [
    {
      "categories": [
        {
          "kind": "other",
          "name": "English entries with incorrect language header",
          "parents": [
            "Entries with incorrect language header",
            "Entry maintenance"
          ],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "Pages with 1 entry",
          "parents": [],
          "source": "w"
        },
        {
          "kind": "other",
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          "parents": [],
          "source": "w"
        }
      ],
      "glosses": [
        "An instrument for determining specific gravity by comparing how much an object stretches a spring when held in a pan hanging in the air to how much that same object stretches a spring when held in a pan underwater."
      ],
      "id": "en-Jolly_balance-en-noun-i4dUz7GJ",
      "links": [
        [
          "instrument",
          "instrument"
        ],
        [
          "specific gravity",
          "specific gravity"
        ]
      ]
    }
  ],
  "word": "Jolly balance"
}

{
  "etymology_text": "Invented by the German physicist Philipp von Jolly in 1864.",
  "forms": [
    {
      "form": "Jolly balances",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {},
      "expansion": "Jolly balance (plural Jolly balances)",
      "name": "en-noun"
    }
  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "noun",
  "senses": [
    {
      "categories": [
        "English countable nouns",
        "English entries with incorrect language header",
        "English eponyms",
        "English lemmas",
        "English multiword terms",
        "English nouns",
        "Pages with 1 entry",
        "Pages with entries"
      ],
      "glosses": [
        "An instrument for determining specific gravity by comparing how much an object stretches a spring when held in a pan hanging in the air to how much that same object stretches a spring when held in a pan underwater."
      ],
      "links": [
        [
          "instrument",
          "instrument"
        ],
        [
          "specific gravity",
          "specific gravity"
        ]
      ]
    }
  ],
  "word": "Jolly balance"
}